Conservation and Restoration of Stained Glass -An Owner's Guide

Home , Art glass, Crown glass (window), Flashed glass, Fonds, Glass art, Medieval stained glass

CHAJ7fER TWEL VE

Virginia Raguin

I. Why Conserve Stained Glass Windows? glass is not stained at aIl, but composed of glass that Delighting the eye with ever-changing combina- has been colored with metallic oxides while still in the tions of colored light, stained glass windows are molten state thus called pot metal. The molten glass functional. as weil as decorative, and commemorate is then blown or rolled, and shapedinto sheetsthat are the religious, social, and economic history of their later cut into segments conforming to a pattern laid comrnunities. While art is too often seenas a peculiar out by the designer. These segments, for example, a province of museums or wealthy private collectors, face, or sections of a robe, receive detailing with stained glass is found in homes, churches and public vitreous paint, ground glass mixed with metallic ox- buildings tbat unite alllevels of society, From stand- ides in a liquid medium. Such painting can be an ardized door panel to complex public commission, extremely simple application of traceline to indicate these windows have been part of America's experi- features, or the creation of three-dimensionaI effects ence, tracing an emerging nation's transition from using back-painting, mat ting, stippling, quill work, or recipient to innovator of great expressions of archi- scratching. The painted glass is fired so that the tectural adornment. ground glass in the paint fuses with the surface of the The simple stained glass set in our earliest churches, glass, producing an image of great permanence. the richly worked windows in Victorian homes, or the The many segments of glass are then joined to- elegantly modern panels of Frank Lloyd Wright, alI gether with narrow lead strips called cames that are are integral parts of the buildings they serve. To lose fitted around the glass segments.The cames are then an original window is to lose the intent of the designer soldered at their joints and puttied to make them wa- and to radically transform the function of the interior tertight. The sections of the leaded window must then space. be placed into a metal, stone, or wooden window The intent of this Guide is to emphasizethe signifi- frame. Additional strength is provided by support bars cance of the stained glass window to American artis- (T Bars) set in the frame of the window and thinner tic traditions, and to provide a means of preserving saddle-bars set on the interior to which the panels of that tradition. The Census of Stained Glass Windows glass are attached. in America was founded to bring together art histori- A number of additionaI techniques can be applied ans, museum profe ssionals, craftspersons in stained to the glass to produce a very wide variety of effects. glass, and preservation experts to research,catalogue, Silver stain is silver nitrate painted on the glass that, and disseminate information on 19th and 20th cen- when fired, turns the glass into various shades of tury glazing traditions. But we cannot study what no transparent yellow. It is often used for hair and longer ex.ists,or what has been so altered by changes architectural and costume details. Color changes can that it has lost its historic integrity. Thus, the conser- also-be achieved usingflashed glass, consisting of a vation and restoration of stained glass is of prime thin layer of colored glass fused onto a clear , or importance, and to achieve a better understanding of differently colored sheet. Using abrasion or acid- these practices, we offer this Guide. etching, sections are cut away in the colored layer to 2. What is a Stained Glass Window ? produce a two-tone result. Enamel colors, of alI va- (See Glossary for italicized words} riety ofhues, were introduced in the Renaissanceand A stained glass window can appearin many forms. were often used in the 19th century and in today's Essentially it is an arrangement of sectionsof glass set modern panels. Many stained glass windows are into an architectural framework. Traditional stained actually sectionsof colorless glasspainted with enamel

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coloIS. flfed and then set in an architectural frarne. Lee, Lawrence, and others. Stained Glass. New Thesewindows often resemblepaintings more closely York: Crown Publishers, Inc., 1976. than Ihey resemble medieval stained glass, but they 3. Dangers or Poorly Advised and Over-Zealous are still important manifestations of the glazing art. Restortion Even windows almost devoid of all color, such as (See Glossary for italicized words) grisaille windows, claim our respect. Thesewindows Even the most well-intentioned program or resto- depend for their effect on the strength of the leading ration can have disastrousconsequences. Every owner patterns and the subtle use of trace-Iine or variations or person responsible for stained glass windows must in surt-acetexture. be aware of potential dangers. We have seen, and Since the late 19th century many new glazing quite recently, shockingly bad restorations commis- techniques have been introduced. Opalescent glass, sioned by well-meaning individuals. Some deplor- glass with variegated colors produced by mixing the able examples deserve to be mentioned. still molten glass from different pots, gave a whole In a church in Connecticut, Tiffany windows were new palette to the stained glass designer. An irides- "restored" without removing them from the building. cent sheen was often added by exposing the hot Their badI y bulged panels were reattached tl) existing opalescent glass to metallic fumes while in the an- saddle bars with wires pierced through the leadcames. nealing oven. Additional treatment to this glass That some of the glass cracked in the process or that brought new effects. Confetti glass received multi- few additional and needed saddle bars were added to colored chips, drapery glass was manipulated during minimize stress did not seem to concem the restorer. the cooling process into ridges and furrows, and often Sheets of Plexiglas cut to fit the window frame and textures, such as those in ripple glass, were added by cemented in place with caulk were passed off as variations in the rollers or the surface of the bed on protective glazing. No attempt was made to fabricate which the glass rested while cooling.1n windows of the "opalescent ela, " often only the hands or faces of frames for their glazing, so its effectiveness is probably of short duration. Unfortunately, this fast but the figures were painted, all other effects being certainly not cheap type of restoration is all too achicved through variations in the glass itself. commonly foisted upon churcli congregations who Changesin the size and shapeof the glasssegments have been pressured to trust the name of an old firm. themselves have transformed the modem image of Other tragic incidents of unprincipled restoration the stained glass window. P lating. or the use of two or can be cited in a landmark church in New Y'ork City, more layers of glass set one behind the other. often renowned for its 19th century glass. Here some deli- adds conJiderable weight to a window, although it cately enameled windows were beginning; to show pennits some spectacular effects. Non-figural win- deterioration of the colored enamel. The restorer who dows or borders often display beveled glass. glass repaired these windows stripped them do,'..n to the whose edges have been ground atan angle, orjewels, bare glass and completely repainted the scenesin bis sometirnes cast nuggets that refract light. The most own style of unbelievable crudeness. If he mlide a dra11]3ticchange. however, is the dalle-de-verre. or cartoon of the original, it was unrecognizable in the facered glasswindow, rejecting the traditionalleaded finished product Thesewindows have been destroyed systemior a matrix of cernentor epoxy resin. For these as effectively as if the restorer had thrown a rock windows, slabs of colored glassare broken or cut with through them. a saw, then chipped around the edges, and set in a Repainting and reflring glass has not been unusual pattern around which the matrix is poured. Once in restorations, again often destroying the window in hardened, the matrix with its embedded faceted seg- the process. From another well-known an(][wealthy ments of glass is unmolded and set in a window. parish in New York cornes a sad examplle. A fine For further discussion of glazing techniques, see: window from the 19308was beginning to show dete- Eskus, Albinas. TheArt ofPainting on Glass. New riorationofits trace linesandmatpaint. The ,glasswas York: Charles Scribner's Sons. 1980. removed from its leads by the restorer, tollJchedup Reyntiens, Patrick. The Techniques of Stained with new paint, refired and releaded. Far ftom stop- Glas.s.New York: Watson-Guptill. 1967. ping the qeterioration of the paint, the repainting bas Duthie, Arthur Louis. Decorative Glass Proc~ flaked off and with it has corne most of thf~original esses.New York: DoverPublications, 1982. paint The window is nowa ghost of its formf~rbeauf;y .~ 164 Temporary conservation attempts, if poorly ad- teriorate, and that the decay is irreversible. It is the job vised, can also damage windows. To protect a win- of the conservator to slow the rate of decay as much dow stored in an important New York museum, as is feasible, and certainly to not do anything that gurnrned paper tape was pasted across the painted might accelerate the deterioration. To guide conser- surface of the glass. In removing the tape some years vators in making decisions about appropriate inter- later, the delicately applied mat paint carne off with vention, national and international ethics of practice the tape. Masking, "Scotch" and gummed paper tape have been established. These ethics are best stated by are often carelessly used to support broken glass in Bernard M. Feilden in bis book, Conservatio~ of transport forrestoration. Tape should be used with the Historic Buildings. greatest care, never on painted surfaces and only for Thefollowing standard of ethics must be rigorously short duration. Skillful touch-up painting, using a full observed in conservation work: ~ sized photo as a model, was able to repair the damage ( 1) The condition ofthe building before any interven- in the case of the museum's window, but proper ~ tion and ali methods and materials used during ~ handling would have made this expensive festoration treatment must be fully documented. unnecessary. (2) Historic evidence must not be destroyed,falsified This Guide should help owners in the choice of or removed. con-servation/restoration procedures.Individuals can (3) Any intervention must be the minimum nel:es- then more accurately weigh the urgency of immediate sary. intervention against the caution in assessing long- (4) Any interventi(jn must be govemed by unswerv- tenD needs.Do not become a "deplorable example". ing respect for the aesthetic, historical and 4. Philosophy of Conservation/Restoratjon physical integrity of cultural property. Stained glass windows are at once works of art and Any proposed interventions should ( a) be revers- architectural elements. How does one begin to define ible, iftechnically possible, or (b)at least not preju- a philosophy of conservation/restoration that is con- dice afuture intervention whenever this may become sistent with the windows' dual role as art and artifact? necessary; (c) not hinder the possibility of later Fortunately, we can draw from precedents set by access to ali evidence incorporated in the object; (d) architectural conservators that are easily adaptableto allow the maximum amount of existing material to be our work in stained glass. retained; (e) be harmonious in colour, tone, texture, Throughout this Guide, three levels of intervention form and scale, if additions are necessary, but should are discussed: conservation, restoration and adapta- be less noticeable than original material, while at the tion. same time being identifiable; (I) not be undertaken by CONSERVATION. The objective of conservation conservator/restorers who are insujJiciently trained is to retain the existing design, material and aesthetic or experienced, unless they obtain competent advice. value of the stained glass window. This may require Feilden is former Director of the International nothing more than regular maintenance, or it may Centre for the Study of the Preservation and the require direct intervention to ensure the continued Restoration ofCultural Property(ICCROM) in Rome, structural. historic and artistic integrity of the win- Italy. He was also conservation architect for such dow. noted projects as St. Paul's Cathedral, London, and RESTORATION. The objective ofrestoration is to York Minster. retum the stained glass window to its original fonD and design ( or in rare casesto the fonD and design of 5. Planning Y our Conservation/Restoration Cam- a later period of significance). This may include the paign removal of later repairs, or the replication of missing I. Study and Evaluate the Windows or damaged portions of original work. If at aIl possible, consult with someone trained in ADAPTATION. The objective of adaptation is to the study of the American Decorative Arts, an art or rework the stained glass window for a new installa- glass historian, local historian, theologian, or a spe- tion. This may involve adding or removing glass to fit cialist in stained glass to help with the study of the an opening of different size or configuration, or windows. They can help you evaluate your windows preparing a window for museum display. Profes- for their significance to your community and its sional conservators recognize that ali materials de-~ history. Their objective opinion can aid you to edu-

165 Virgini.~

cate the congregation, Board ofTrustees, or public to how it may relate to the total ensemble. Make a the importance of the windows. record of alI memorials or inscriptions, as these Galber aIl of the existing information about the are difficult to reconstruct if damaged. windows, frames, and building. Develop the history 6. Collated records of previous repairs to the win- of the windows from fabrication to the present day. If dows or frames. Identify the studio or craftsperson the ~indows are in a church or public building, who performed the work. Determine if it was an investigate any possible records orphotographs which emergency repair, or a well-thought-out restora- may exist. Make public notices of the search, and tion. Was any of the original fabric or design request any relevant material from parishioners or intent altered by the repair/restoration?' members of organizations which made use of the 7. Any catastrophes (i.e., fire, flood, etc.) or nearby facility .This information may be found in copies of dernolition or construction which may have af- old joumaIs or public relations material produced for fected the windows. special events which occurred withjn the building. Gather the above information, collate and make cop- Old photographs may be immensely useful, whether ies so that the originals may be stored in a safe place they are professionaIly taken or are family snapshots away frorn the building (i.e., safe deposit box, mu- from a wedding. Try to be creative when searching for seum store room, etc.) You are now ready to proceed this materiaI. A case in point occurred at a large to the next phase. church which had been destroyed by fire, which also II. Survey the Existing Conditions of the struc- consumed the documentation covering their win- tural and Decorative Fabric of the Window dows. However, the church had been used to photo- A. Purpose graph a wedding scenefor a movie some years previ- Regardlessof whether a restoration program is possi- ous to the fire, and photographs of the windows ble in the near future, as soon as you realize the existed in the film library of the movie studio. Draw importance of the stained glass you may possess, a from the above and collate the information gathered complete survey and update of documentation should for the building and each of its stained glasswindows. be done. The purpose of this is threefold: Kno~. as much as possible about the following: 1. The survey allows you to begin monitoring the A. The Building changes in the condition of the windows. Over I. Date construction began and date completed. time the serious problems will become self-evi- 2. Types of building materiaIs used and their rela- dent, so that if and when restoration money be- tive quaIity and the construction techniques em- cornes available, it will be weIl spent. ployed. 2. The completion of photo documentation may be 3. Architect, designer and builder with any avail- invaluable if the window is seriously damagedby able information about them. accidental or deliberate forces. 4. Original drawings, elevations or plans of the 3. Historically, the documentation you develop wil1 structure. be of great interest in the future to art historians, 5. Major alterations or repairs to the building or conservators, owners/caretakers and concerned interior furnishings. These are important because members of the public. they may alter the way in which the windows If a restoration program is feasible, then a survey is were originaIly designed to be viewed, by expos- essential. It will serve the above purposes, as weIl as: ing or covering parts of the window. This infor- 1. Help to create a set of specifications, so that the mation may also be helpful in dating undocu- job may be put out to bid. mented window restorations. 2. Help church members or public officials solicit B. The Stained Glass grants or donations toward the restoration effort. I. Artist/designer with information on other com- B. The Survey missions in the area. 1. A floor plan should be produced, or existing 2. Fabricating studio. elevation drawings used, to locate and identify 3. Date fabricated and installed. the windows. A logical nurnbering systern should 4. Donor or person who commissioned the win- be devised so that the individual panels, parts of dows. the window and the windows as a whole can be 5. The subject mat ter of the individuaI piece, and identified. AlI existing documentation should be i 166

~ Conservation and Restoration of Stained Glass -An Owner's Guide

Î ~ keyed into this system. experience photographing stained glass windows. If 2. A Complete photographic documentation of the the proposed photographer has no samples, shoot a stained glass, frames, and associatedarchitecture test roll to guaranteea high degreeof quality .A 28mm should be produced (See below for minimum X 85mm macro zoom lense is ideal for most shots photographs required). specified. 3. A physical inspection of al] aspects of the win- The photo set should include the following: dows should be made. You should be prepared to 1. Interior overall views of window with: provide ladders or scaffolding so this can be done a. Reflected light to illustrate surface texture correctly. If funds allow, the removal of a sample and coloration and to differentiate leading pattern panel can be extremely helpful to delineate the from possible painted details. probJemswhich may exist and thereby to ascer- b. Transmitted light toindicateobserved colors tain an accurate estimate of restoration costs. and painted details. (See below for suggested physicaJ inspection 2. Interior detail shots of special situations such as: checkpoints.) a. Installation details (i.e., sill detail, typi- 4. During the survey, be sensitive ta proposed cal meeting joint, jamb detail, head detail, changes to the windows and what the structural, support bar attachment to leaded panel and aesthetic and historical effects may be, such as: supporting frames). a. Addition of, or removal of, protective glaz- b. Damaged areas (i.e., bulging s e c t i o n s , ing or screening. failing borders or support bars, areasof possible b. Possible sealing of ventilators which are no impact, etc.). longer used. (Due to the constant opening c. Areas of paint deterioration-this is particu- and closing of ventilators, the glass in these larly important if immediate restoration is not moving sections is more at risk than if they possible, for monitoring paint loss and to were stationary.) reconstruct the originallinework when restora- c. Ways to better support the stained glass and tion is possible. surrounding frame, or to better seal them d. Studio signature plates to identify the maker against the elements. for insurance or historical purposes. d. Possible addition of artificiallighting sources 3. Exterior detail shots of special areas to iIluminate at night, or replace daylight a. Pertinent installation details blocked by subsequentconstruction that al- b. Protective glass details tered originallighting conditions. c. Special problems (i.e., condensation frame 5. By inspection of the existing documentation and rot or rust, displacement of window elements). physical inspection of the setting, verify that the d. Attendant architectural details which pres- windows are in their original frames and location. ently or in the future may affect the windows Although al] of the above work can be accomplished (i.e., repointing problems, movement of by, or with the aid of, a stained glass consultant or stonework. etc.). competent restoration expert, you may also wish to Depending upon the artistic and historic value of consult an architect. An architect's services would be the windows, budgetary concerns, and the needs of very useful in discerning the condition of the related the owner, this list may be modified. But for accurate fabric of the building (i.e., roof, stone or woodwork, documentation and sensitive restoration purposes, major structural elements, etc.). Pains should be taken this list represents the bare minimum requirement. to secure the services of a competent preservation D. Problems to be Discussed with your Consultant/ architecL The sensitivity and knowledge needed to Restoration Studio preserve historic buildings are often different from 1. Stained Glass Panels that of new construction. a. Lead Matrix C. Suggested Photographic Documentation 1. Does the panel feel solid or does it bend The photographs should be 35mm color transpar- easlily? encies and black and white prints. If fonds are avail- 2. Inspect the vitality of the lead came. Are able for a professional photographer, al] the better, there visible cracks and signs of fatigue? but a minimum requirement would be a person with How does the lead flange respond to a gentle 167 Virginia~guin

bending? Does it flex or does it crack easily? 5. How are the windows held into the frarnes? Are sections of lead came missing? What is the condition of the caulk or putty 3. Are there many broken solder joints? level? 4. Has the putty fallen out or been washed out 6 What is the condition of the sub-framing from under the lead flange? support of the frames? b. The Glass 7 What is the possibility of breakage due to 1. Is there broken or cracked glass? Does the removal? breakage seem to follow a pattern through- 8 How are attendant problems in the building out the window, or is it the result of unrelated (i.e., roofleaks, etc.) affecting the windows? impacts? When the above survey has been completed, the 2. What is the condition of the glass paint? If it decision must be made as to whether the work can be is deteriorating, does it appear as though it performed in situ or if the windows must be removed. was originally weIl adhered? How effective It should be remembered that windows are imperiled would consolidation be? (Consolidation of when ever they are removed from their frarnes. In paint is a process whereby loose or flaking general, the windows should be handled as few times paint is re-affixed to the glass.) as possible. 3. Is the glass corroding? If so, does it appear to E. Documentary Summary be due to a water condition or a special AlI of the information which you have gathered by chemical condition ? (Glass corrosion may be following the guidelines of Sections I and il forms the the result of attack by water, chemicals, or record to date on documentation of the windows. It is possibly biological agents. It is important to extremely important that before any work (from the ascertain the type of attack so that the prob- most minimal cleaning to complete restoration) is lem may be solved.) started, that your documentation papers be available c. The Support System to the conservator/ restorer. Make sure that any work I. Are the tie wires or support bars separating done to the windows is accurately recorded so that the from the window? Are they missing entirely? documentation is always current and complete. It ,i 2. Are there bulges in the window? If so, are cannot be stressedtoo often how important this record they due to poor support design, poor leading of the history of the windows is to future restorers, pattern, or failure of the lead matrix due to historians and concemed members of the general meta! fatigue? public. 3. How are the support bars attached to the Ill. Choice of Conservator and/or Restoration stu- frames? For the support bars to function dio effectively, they must be attached to the THIS IS THE MOST IMPORTANT DECISIONto be frames in some way. made for the preservation of the windows. Put tirne do Insta!lation/Frames and effort into checking the references of proposed I. What is the type and condition of the frames? studios. Make inquiries of objective institutions, such Are they salvageable? as the conservation department of a large museum, or 2. What is the type and condition of the meeting a not-for-profit conservation or preservation group, joints? Are the individual panels adequately and the State Historical Preservation Office. supported? Longetivity of a studio does not insure quality; man- 3. What is the condition of the ventilators? Do agementchanges may result in lowering of standards. they operate smoothly? Is the frame material Try to deal with a studio where the owners maintain in good shape? If replacement is necessary, knowledgeable responsibility for the quality of the will the new ventilators be of the same di- work. Inspect previous work and speak with former mensions so that the historic glass will not be clients. Note weIl, the "hest huy" may not he the altered? This is always possible, albeit, more lowest hid. The owners/caretakers of the ~,indows costly. should visit the prospective studios to see 'work in 4. Is there any type of protective glazing and progress. Be wary of a studio owner who refu:;es such how is it installed? Is it causing any conden- a visit, no mat ter what his/her reasons may be. sation problems? The owners of the studio must have a special

168 sensitivity for the preservation of historic windows, do not clean at ail. and a dedication to do what is best for them. They 1. If the paint is very stable, the section may be dipped must be able to communicate clearly, respect the in clear water or neutral pH solution restoration philosophy of the owner/caretaker of the 2. Use methylene chloride or a solution of windows, and yet voice their opinions if they feel the dimethylformamide (DMF) .thickened with cel- owner's philosophy may negatively affect the ulti- lulose to remove old putty. This mixture may also mate quality of the restoration. be used to remove house paint which has The studio must also know how the adjacent-prob- inadvertantly been applied to the glass during lems of the building may be affecting a window, as building maintenance. weIl as how to protect the window if work is done near 3. Under very controlled conditions mechanical re- them by other trades. The studio must have experi- moval of dirt may be done with the following: ence with setting scaffolding and methods of lower- glass fibre brushes; wooden or metal scraping ing and transporting the glass panels, once they are tools. Extreme care should be exercised, and removed. sample pieces should be inspected by a qualified 6. Conservation/ Restoration Procedures technician with a microscope to detect possible I. Cleaning of Stained and Leaded Glass damage to the glass Before any cleaning of painted glass is begun, the All of the aforementioned techniques demand a high paint should be inspected to insure. that it is firmly degree of sensitivity and supervision so that none of attached to the glass, that is, "stable" and will not be the applied decoration is removed. If the windows are removed ~ith the dirt. This process is highly techni- not painted, the same guidelines should be followed. cal and should be determined by a professional famil- None of the "cleaning methods to be avoided" should iar with paint problems. Note weIl, that the most be used. efficient method of removing the dirt from the glass II. Removal and Transport ta Studio may not ulùmately be the best method to use due to Before any removal is started, review the documenta- the possible damage it may do to the glass or the paint tion to insure that it is current. A minimum require- layer. Where there is evidence of paint deterioration, ment would be in-place photography of any window it is better to half-clean the glass than risk the further to be removed. Review with the conservator/restorer loss of painted detail. the techniques which they intend to use. Know all you A. Cleaning Methods to be Avoided can about the following: 1. Any application of, or immersion into a lye bath. A. Insurance-the owner should receive a certificate 2. Stearn or high pressure cleaning system, such as of insurance from the studio which lists aIl cov- those used to clean masonry . erage in force. Compensation, general liability 3. Any type of mechanical or air abrasive (sand and any other type of insurance specified by local blasting) equipment (except for the very.control- code should appear on this certificate. The owner led methods discussed below). (or studio) should further insure the windows 4. Any acid, caustic or abrasive cleansers, such as against damage caused by transport, vandals, or oven or bathroom cleaners, hydroflouric or other otherperils not covered by the general multi-peril acids. arnmonia-based window cleaners, scour- policy of the studio. ing powers or steel wool. B. The removal of the glassis often a difficult and 5. Note weIl that if any of the above are being used demandingjob. Damage may occur to glass dur- in the vicinity of the stained glass (to clean ing the removal process. This may be caused by: masonry, etc.), the windows must be protected. the poor condition of the window; rock-hard B. On-site cleaning should be limited to dusting, or putty; distortion of the framing members; or washing with a soft cloth and soft water (distined unanticipated setting details. Therefore, extreme water is preferred, hard water should be avoided). caution should be exercised and specific setting C. ln the restoration studio, the following procedures details recorded in the documentation. may be used to further clean the glass. Until the C. If the leaded panels are in such a poor state of stability of the glass paint is verified, alI cleaning disrepair that they may fall apart upon removal should be done on a light table and closely monitored. and further damage the glass, special tape may be Again, if cleaning win causeany further loss of paint, usedto hold the panel together. This tape must not 169 Vir~ ~guin

be put on the paintedsurface of the glass.Masking monitor endangered areas. tape, filament tape, duct tape etc., must not be 7. Cataloguing, and noting in existing documenta- usedunder any circumstances. The only tape that tion, the removal of panels or pieces of glass. can safely be used is that in which the backing of B. Storage of stabilized glass. If possible, the glass the tape does not dissolve in the same solvent as should be stored in a vertical position with suffi- the adhesive part of the tape. In general, tape cient packing for support within wooden crates. should be used sparingly. Tape should be re- Any tape used for removal purposes should be moved by skilled personnel as soon as possible. removed before packing. If the panels are too This should be done with solvents, not by simply damaged to store vertically, they may be placed pulling it off. Tape will pull offpaint. on trays within a horizontal rack arrangement D. The removed leaded panels should be transported similar to a pie-safe. The crates or racks should be and stored in a vertical position with sufficient clearlymarked and placed out of hann's way in a pocking material to prevent breakage. If the pan- cool, dry, ventilated safe place. eI.s are so damaged that they cannot be kept C. Storm damage/emergency repairs/insurance esti- vertical, they should be supported independently mates. If a local glazier is called upon to do on trays of sufficient design to keep the panels as emergency repairs, do not feel obligated to him or f1atas possible. They should be stored away from her for the actual restoration work. It may not be moisture and damaging chemicals. possible to follow the previously suggested se- E. Nier the panels have been removed, the frames lection processfor a restorer when rain is actually should be inspected to seeif they or other related pouring in through a broken window. Find a local setting details contributed to the deterioration of glazier to temporarily weather-proof the win- the stained glass panels. Some possible problems dow. Pay him or her, and feel no further obliga- ta look for are: tion. This is true of people who may give you I. Prame movement, which when transferred to the estimates for insurance purposes, also. Do not sL1ined glass through rock-hard putty, causes choose restorers becausethey are the first to see breakage of glass. the job; choose them because they are the best qualified to do the job. 2. Architectural or protective glazing details that ~, encouragecondensation, orinhibit rainwaterrun- D. Do not's of Stablization off. 1. DO NOT use tape of any kind to stabilize win- III. Stabilization Program dows. A. If the current survey indicates that a permanent 2. DO NOT use silicone, roofing tar or other caulk materials to stabilize windows. loss of glass is imminent, but it is not financially 3. DO NOTmislead yourself or others by thinking, feasibleto complete the required restorationwork, "it's been that way for years, it won't fall apart." a stabilization program should be cansidered. Once a window is gone, it's too late. This is composed of the following: IV .Conservation and Restoration of the Windows I. Removal of panels in danger of falling out, and in the Studio tao far gone to stabilize on the site. A. Verify if complete and current documentation 2. Removal for storage of those individual pieces of exists, including photographic documentation. gIass in danger of falling out. Plan for photography during restoration proc- 3.Addition of storm panels to weakened areas to essesto illustrate techniques employed. Prepare reIieve the wind loads. rubbings of stained glass panels with notations 4:. Sandwiching areasof the windows between rigid indicating damaged areas. sheetsof Plexiglas to give them temporary sup- B. Analyze the windows to discover why they failed port. (This must be done in such a manner so as (insufficient reinforcement system, weak lead, nat to trap condensation.) fatigue of structural elements). Begin to think of -.Possible5 erection of barriers so that the public ways to improve the structure and restore the cannot inadvertently damage the windows. aesthetic appeal of the window. 6 Prequent visual inspections of the windows to C. 1. If the windows are to be releaded. Separatethe glass pieces from the lead cames. 170 ~ ç,

Conservation and Restoration of Stained Glass -An Owner's Guide

2. If the windows are not to be releaded, remove the aestheticsof the window. The leading pattern only thoseparts necessaryto facilitate the flatten- chosen should augment the support system, with ing of any bulges (support bars, critical pieces of the continuous leads being perpendicular to sup- glass, plating, etc.) Remove individual pieces of port bars wherever possible. glass which may be broken or damaged. 2 If the panels are not to be related, the following D. Clean glass as directed at the beginning of this pertinent steps should be executed: chapter. a. Flatten all bulges. This is accomplished with E. Repair individual pieces which are broken or a combination of weights and moderate dry damaged. This step requires a technical knowl- heat or soaking in warm water, depending on edge gained through experience as weIl as an the circurnstances. It is important to note that aesthetic sensitivity. The restorer must also re- if the bulge is of medium to severe in its spect the history of the window and the owner's dimension, it is impossible to repair in place. chosenpreservation philosophy. This step of the Beware of workers on ladders with little restoration may involve one or more of the fol- rubber mallets. lowing procedures: b. Reinserttherepairedindividualpieces, which I. Copper foiling broken pieces of glass together were removed or rnissing,into the leads. ~d soldering on copper wire for additional sup- c. Remove the flanges of meading leads and port. apply copper wires to remaining lead hearts. 2. Edge gluing with silicone or epoxy glues. G. Re-putty the window. The window should be re- 3. Plating with a thin piece of new glass which has puttied with a linsead oil or equivalent putty. The been slumped in the kiln to conform to the reputty should be forced under the leads, with all paired piece of glass. residue carefully cleaned away. Do not use Port- EXTRAORDINARY TECHNICAL AND ARTlSTIC land cernent or silicone to re-putty , SKIU IS REQUIRED FOR THE FOUOWING H. Attach reinforcement system. This would include 4 Restoring lost or faded painting of figural ele- the original plus any modifications indicated by ments by adding a painted plate behind the origi- the cause of failure of the original system. This nal piece. Thus the historic worth of the window may include: is preserved. I. Copper tie-wires and round bars. 5 When sections are missing (notjust cracked) cut 2. Brass, steel, or zinc bars or fins soldered directly and paint new replacement pieces to closely to the panels. match existing. These pieces should be identified 3. Addition of clear glass plating. This may include and dated on their edge where the lead will cover additional glass plates to transfer the weight of the identifying marks. original glass plates to a structural member such 6 Consolidation of the paint layer employing a as a "T" bar or the frame. silicone/epoxy system, or other proven method. 4. The insertion of steel bars into the lead cames 7 Infilling with colored epoxy or acrylic or polyes- during re-Ieading, where it can be accommo- ter (may be unstable if exposed to the elements). dated. 8 Touching-up with cold paint of decorative ele- I. Prepare windows for reinstallation. Visually in- ments with acrylics (may be unstable if exposed spect aIl work performed for high quality and to the elements). completeness. Amend documentation to reflect Remember, every effort should be made to retain restoration. original glass and to employ reversable restoration J. Donot's of Restoration processes. I. DO NOTremove any panels without photogra- F. Repairentire window. phy in place. (I) Relead the panel with a lead of the proper alloy. 2. DO NOTuse silicone to attach bars, seal up holes This should contain antimony, tin, copper, silver , in windows, caulk over holes in the glass. Sili- and lead. Pure lead is very weak and is not good cone has limited uses in the stained glass trade. It for stained glass windows. Consider altering the is often abused. profile of the existing lead came to a stronger one, 3. DO NOTthrow away glass becauseit is crac~:ed. but be conscious of the effect this may have on Determine if it can be restored first.

171 Virginia R.~ ,

4. DO NOT assumethat a window most be releaded window, or heatuponly portions of the glass. The becauseit has bulges or other defects. Many such effect is more natural, since the light is diffused windows cao be repaired in the existing leads. by striking the rear wall before it passesthrough 5. DO NOTattempt to flatten severebulges in place. the windows. The window may be damaged more than it is E. Windows can also be reset within newer win- helped. dows. Here great care must be taken to preserve 6. DO NOTuse Portlaodcement or silicone to reputty the aesthetic integrity of the original. The reset- the-window. ting must be structurally sound and also take into 7. DO NOTuse surfacecoatings, such as varnishes, account the color, range of value, and subject polyurethanes, etc. matter of the window. Patterns in decorative 7. Adaption to Alternate Installations windows can often be copied, and thus continued Although it is always preferable to maintain windows in their new setting. It is far more difficult to in their original setting, there is sometimes no way to approximate the painting style of an older win- presef\'e a window but to remove it to an alternate dow and, even if attempted, the costs are quite installation. Buildings may be destroyed, or renova- steep. Often it is better to set a colored, figural tions compromise the safety of a window. ln unusual window in the midst of a neutra! or geometric cases,an extremely valuable window is transferred to pattern. The colors and values selected for the a museum or private collection. Should an owner find setting should not overpower the window, but that the original architectural setting of a window is enhanceit, much the way a mat and frame do for no longer viable, several alternatives should be con- a painting. sidered- 8. Security and Insurance A. If a building is slated for demolition, for example As you begin to research your window, you may realize that it is indeed valuable. In this case, you an older church facing destruction to make room for a hospital, windows can be reset in certain should consider protecting it from theft, vandalism, or damagewhile it is in your building, and insuring it ar~ of the new building. In the case of the hospital, the meditation room, or the lobby seem during restoration. viable areas. Thus a community can preserve its Replacement Value vs. Market Value. In order to determine the monetary value of your heritage by maintaining a link between the old window, it will have to be appraised. This appraisal is use and new use of the site. See the following not the sameas an appraisal of an antique or painting. section Security and lnsurance, for help in plac- Most smaller, more portable items are appraised at ing a value on old windows when arguing for their market value by licensed appraisers, auction their reuse. B. Windows taken from one portion of a building, houses,antique dealers, or museum or gallery profes- for example a destroyed Sunday School room, sionals. Stained glass windows, however, rarely have a market value, except in rare cases of very weIl can be converted to a screen separating offices, a known designers, such as Frank Lloyd Wright. This hallway, or the entrance to a chapel. is due to a number of reasons.First, stained glass is an C. A false wall can be constructed againstan interior architectural element, and sometimes a window will wall and windows set into it. The wîndows would lose much of its significance if it is removed from the then be lit by artificial light. It is important to building for which it was designed, or if a series is leave room between the false wall or panels and broken up. Often windows are difficult to sell because the original wall for periodic inspection and of their size or their imagery .But, more importantly, maintenance of the windows. most often the market value has no relationship to the D. Light boxes are more flexible than a wall instal- replacement value: often a window will be sold to lation and allow the owners to move the location make room for a replacement, which ends up costing of the windows, should this become imperative. many times more than the piece received for the It is preferable, in the caseof artificîallighting, to original. place florescent tubes on the inside of the window Stained glass should therefore always be appraised wall, that is, next to the window, not behind it. at its replacement value by a experienced stained Thus, the light does not shine directly through the glass craftsman, who has worked on projects of a l72 I ~

Conservation and Restoration of Stained Glass -An Owncr's Guide

similar scope. The replacement value is a realistic any way with the stained glass or the protective estimate of what it would cost to replace the window glazing should be considered; old-fashioned foil tape with a theoretically identical copy, if the original is not only out-moded, it should never be applied to were destroyed; in other words, what it would cost to stained glass. Infra-red sensors or sensitized mesh build that window today. Do not look for the least screens,currently available, should be investigated. expensive contractor to do this estimate, becausethis If the window is to be removed for restoration, the is the value on which your insurance will be based.Of opening from which it came will obiously have to be course, if your window is a rare medieval piece, for closed to the weather and made secure. Plywood, example, it could never be replaced, which is why the Lexan or Plexiglas, or glass may be used to close the replacement value js a theoretical figure. If this is the opening; the size, location, and type of frame wiIl case, a fine arts appraiser should also place a value on dictate the type of closure to be used. This should be the window, and the piece should be insured for the installed in such a way that would be very difficult for higher of these two figures. unauthorized persons to remove. Access to alI scaf- Protection (cf., 10 Protective Glazing) folding or bridgework should be secured also. The Regardlessof the value of your window, it should restoration studio should be preparedand expected to be protected from theft, vandalism, or breakage, in deal with this issue adequately, and it should be areas where this is likely to occur. For instance, if discussed thoroughly with the owner. your window is installed in a location where an lnsurance. attempt at theft would not be noticed immediately, If your windows are of significant historic or such as a mausoleum or the rear chapels of a church, artistic value, you may wish to insure them for fire, it is important to secure the window physically, theft, and vandalism,Tegardless ofwhether they wiIl instead of or in addition to installing an alarm system. be restored. As discussed above, the insurance value A decorative iron or steel grille could be used, al- in this instance is based on the replacement values of though its shadow might be visually disruptive from the window. Contact your local museum or historical the interior. Lexan, an unbreakable polycarbonate society for the names of reputable art insurers in your sheet material, connected to an aluminum or steel area. If your windows are to be removed for restora- frame from the interior, is very effective. Its exterior tion, they should be insured. AIso, it is the resPOnsi- appearanceis similar to that of plate glass, although bility of the owner to demand the studio to produce it is not as highly reflective. If this is used, be sure the evidence of insurance coverage for theft, fire, and space between the Lexan and the stained glass is breakage from the moment of removal. This must vented. (Other clear sheet material, such as Plexiglas include transportation. or acrylic~ are not unbreakable.) If other restoration work is taking place near the 9. Re-Installation of Restored Panels stained glass, such as cleaning, repointing, or paint- A. Before installing the restored glass panels, deter- ing, care should be taken by the owner that the stained mine that alI pre-existing problems with the building glass is protected from damage. Windows should be that were detrimental to the glass have been repaired. covered ~ith plywood, whether the work is interior Re-installation should be carefully coordinated with or exterior. Edges of the plywood should be caulked work of other trades so that any scaffolding erected is if any kindof liquid or air-abrasive methods are being utilized efficiently, and so that the glass is not put at used in the vicinity of the windows. A stained glass risk. The work of other trades should be complete craftsman should do this, rather than the cleaning before the glass goes onto the scaffold. This coordi- contractors, who may not know how to deal with a nation is best handled by the project architect. stained glass window. B. Have the conservator/restorer inspect the frame to insure that any deficiencies discovered during the Security. survey or removal phases have been rectified. This ln areas where vandalism and breakage are not may include the alteration of certain aspects of the likely and a more aesthetic solution to security is original frame, if time has proved certain original desired th:m those cited above, modem alarm systems design details to be faulty. cao be adapted for use with a stained glass window. C.The following is a brief discussion of the types of Only those types of alarms which do flOt interfere in frames into which stained glass may be set. This list 173 .

Virmnia ù2uin

is not comprehensive, but the majority of windows ferent construction details. It is important to have a are imtalled in the following ways: restorer/conservator who is familiar with many dif - 1. Stone. There are two types of stone frames; one ferent types of frames. One should always investigate with a groove that is sight size on the interior and the possibility of restoring existing frames asopposed exterior of the building; or one with a rebate to installing new ones. Not only will the restoration be which iscut into the exterior of the stone. This more historically correct, but the end product may second type may have a steel subframe, or the very weIl be more durable. leadedglassframe may be glazed directly into the D. Meeting joints. Most large stained glass windows stonerebate and held with clips and a putty bevel. are a series of panels which sit above one. another. With minimal maintenance, stone frames may Where these panels touch is called the meeting joint. last for hundreds of years. Inspect the stone for Whenever possible. it is preferable to have each panel possible deterioration due to chemical attack (i.e. supported independently by means of horizontal pollution). lnspect the joints for possible muntin (i.e. "T" bar). This muntin should be physi- repointing work. Always prime the stone groove cally attached to the vertical mullion. or rebate with shellac or other suitable primer E. Sealants. A wide variety of sealants are available before applying putt y. Apply a back bed of putty , on the market today. It is extremely important to setthe glass with clips and apply an exterior putty match the proper type of sealant or caulking to the bevel. special circumstances of each installation. The re- 2. Wood. Many historic windows are set into wood storer/installer should subrnit product literature so frames. There are two basic types of wood frames: that the owner/architect may judge on the appropri- those with retaining moldings and the rebate atenessof the material proposed. After selecting the type. Occasionally, one finds a groove similar to proper material. make sure that the manufacturer's the stone setting. To prepare for installation, the recommended installation procedures are: followed wood must be primed. Apply a back bed of putty (e.g. temperature limitations. need for primer. type of andset the glass.The glassisretained by moldings substratecaulking will adhere to. etc.) or is nailed to the wood with non-corrosive nails and a putty bevel is applied. Inspect the wood 10. Protective Glazing frames for signs of rot or severeweathering. Most The installation of protective glazing is an aspect wooden frames can be restored. If properly re- of many restoration projects which is often not given stored and maintained, wood frames can last for the thought and attention needed to insure a proper hundreds of years since they are more durable job. Protective glazing systems, when correctly in- than most metal frames, especially in areas of stalled, may greatly increase the longevity ofhistoric high pollution or salt air. glass, and may decreasethe overall energy require- 3. ,\fetal trames. These may be of steel or alu- ments of the building. When incorrectly installed, the minium, and sometimes, brass or bronze. The protective glazing may greatly detract from the aes- IWOtypes of frames areones with applied molding thetic beauty of the windows and the building, and set or putty bevel rebates.The installation procedure up conditions which may ~ctually destroy the glass. Ï5 similarto that for wood frames of similar type. (For example, it may cause condensation, additional ~fetal frames have to be carefully inspected for stress to the existing frame, and other serious prob- rust or corrosion. While meta! frames can be lems.) The best protectiveglazing system for any restored, the process is more difficult ~an with parrticular building is a sensitive compromise be- wood frames. ln insta!ling new meta! frames be tween the following factors: degree of protection; particularly careful to avoid the contact of dis- aesthetic effect; cost. The priorities for each of these similar metals. This may cause severecorrosion factors should be clear to the owner/contractor before due to galvanic action. Make sure the architect's choosing a protective glazing system. or the manufactufe's specifications are followed A. Types of glazing systems. I. Leaded panels. Leaded glass panels that either ,ery closely. duplicate the major leads of the design or are of a The above frarnes are found inmany different shapes geometric pattern may be fabricated to protect the and configurations. There may be hundreds.of dif- historic glass from the elements and enhance the 74 f ;l;

, I :it r, ~ aesthetic beauty of the exterior of the building. This 3. DO NOT screw faste acrylics or polycarbonates to type should be chosen if aesthetic effect is of the existing frarnework unless special installation details highest priority .The main disadvantages of this sYs- are specified to allow for the expansion and contrac- tem are increased cost and its vulnerability to deter- tion of these materials. mined attack by vandals. 4. DO NOT destroy the aesthetic beauty of the exte- 2. Laminated or tempered glass. This system can be rior in order to protect the stained glass. installed sensitively so that the negative effect on the Il. Glossary exterior beauty is minimal. It is less attractive than Abrade (Abrasion). To scrapeaway surface of glass leaded panels, but more attractive than plastic panels or remove the colored layer ofFIasbed Glass witli an which tend to bow. This system offers increased iron point, wheel, or bit. protection from vandals. Acid- Etcbing. processof removing colored flashing. 3. Acrylics or polycarbonates. This system offers the The area of flashing to be removed is f1fSt outlined. greatest degree of protection from vandals or other The rest is masked with bituminous paint. while attack on the glass. The main disadavantagesof this hydrofluoric acid eats through the ex~sed portion to system is the high co-efficient of expansion for both the paler-colored layers below. materials. If this is not properly compensated for in Annealing. Final cooling process in glass manufac- the installation/framing system, it may impart great ture which gives glass its temper . strain on the original frame system to which it ii- Antique Glass. Hand-rolled mouth-blown clear or attached. Acrylics are subject to deterioration from colored glass made by old glass blowing methods. ultra-violet radiation. This may result in acloudingof Armature. The iron, bronze or wood framework the plastic and decreasedresistance to breakage.Both fixed in a window opening to support panels of materials tend to bow and are not very resistant to stained glass. scratching. Polycarbonates are theoretically crack- Art Glass. Commercially designed and mass-pro- proof, however. duced windows, employing mainly Opalescent B. Installalion. Glass. Installation of the protective glazing system may be Back-Painting. Painting on the back or outer surface by one of two methods: either into a secondaryrebate of glass. in the existing frame or into a separateframe that is Badgering (Badger). A method of shading by dab- attached ta the exterior of the original frame. Either bing a matted surface (seeMat ting) with a Badger a method warks weIl; it is the execution of the actual soft brush three to four inches long, in order to installation that is more important than the method. produce smooth or stippled effects on a Wasb ofpaint. The follo\\ing factors should determine the method: See Blender, Stipple I.Possible loss of architectural details. Bay. A single, whole unit of a wall or ceiling compris- 2. Proper weep-holes and venting. The airspace being a series of such units. tween the glass and the protective glazing can be Beveled Glass. Plate glass with edges ground on an vented to the outside or the inside depending on angle that extends beyond the flange of the Came. placement of the window and the climate conditions. Often glazed with zinc instead of lead came. It is essential to avoid condensation between either Blender. Badger-hair brush used for blending Vit- the exteriar or the interior glazing panels. Conden- reous paints on the surface of glass: Also used for sation wiU destroy the lead cames and attack the stippling. See Stipple, Badgering. surface ojthe glass in the space of a very few years. Border. Outer strip of a window, given to omament. 3. Proper allowance for expansion and contraction. See EdgingLine, Fillet 4. Structural ability of exposing frame ta support Boss. Small circular panel of omament, normally set additional weight. in the background of a window. See Medallion, C. Do Not's of Protective Glazing Roundel. 1. DO Nor install without proper weep-holes and Bull's Eyes. The center of a piece of Crown Glass venting. that includes the mark where the pontil was attached. 2. DO NOT expect the installation of protective glaz- Came. Extruded lead strip, usually H-profile, used to ing to obviate the need for a praper restoratian pro- hold together the individual pieces of glass in stained gram. glass window. 175 Virginil ùguin

Canopy. Architectural frame for a figure or scene. glass fused to the surface of another piece of colored Cartoon. Full-size drawing for a window or panel. or clear glass. Catbedral Glass. Commercial, machine-rolled Fused Glass. Piece of colored glass bonded by heat stained glass widely used in the United States. to another sheet of glass. ConfettiGlass. Hand-rolled glass to which chips of Glass. A mixture of silica, potash, soda and lime multi-colored glass have been added in the blowing fused by heating until molten and then formed by process. various processes. Core or Beart. The cross bar of the 'H' section of the Glass Applique. Collage of pieces of colored glass Came. glued with Epoxy Resin to clear plate glass. Crackle Glass. Antique Glass with crackeled tex- G lazier .A maker of glass windows. ture ~.hich has been intentionally introduced in the Grisaille. (I) Blackish or brownish vitreous paint cooling process. Crown Glass. Made by blowing the molten glass into used for painting on glass (2) window or panel or the sbapeof a globe and opening it up by spinning or omamental designs composedalmostentirely of clear twirling to form a flat disc. See MufT Glass. glass. Collet. Scrap or waste glass remainïng after cutting Hammered Glass. Machine-rolled glass whose the pieces for a window. hammered textured side is produced by the pattern on Cylinder Glass .See MufT Glass. the roller . Dalle de Verre. pieces of glass, usually about one Heart. See Core. inch thick and often chipped or Faceted Glass on the Insert. To put one piece of glass into a hole previ- surface. which are set into concrete or Epoxy Resin ously openedin another piece of glass, and the second or sometimes lead. A modem type of glass. piece leaded into the flrst. Diaper, Diapered. .Decoration of a surface with a Isothermal Glazing. System of protective outer regularpattem of geometric or vegetal forms, usually glazing. by Stick Work Jewel. Cast, or chipped, poli shed nuggets of glass Drapery Glass.. Opalescent -type glass formed into inserted in windows for a decorative effect. ridges to resemble drapery folds. Lead. See Came. Edging Line. Band of glass, sometimes with painted LeadLine. A term used in window design to indicate the placement of the lead Came in the actual Panel. designs, placed as an edging around a Panel. See Also used to describe the pattern of Leads in a win- Fille~ Border . dow. Enamel.Opaque vitreous color applied to glass. Leading -up. Assembly of glass with leads. changes to a transparent color during firing. Light. Window opening bounded by frame. Usually Epoxy Resin.Synthetic, colorless adhesive, used in- in series with Mullions between. stead of leading to hold together pieces of stained Mat Paint or Mat ting .Applying a transluscent coat glass. particularly Dalle De Verre. Used to mend of vitreous paint to the surface of a large area of glass. broken glass. Medallion. Large circular Panel with figures. See Etching. See Acid-Etching. Boss, Roundel. Faceted Glass. See Dalle De Verre. Mending Lead. Thin lead, also called a dutchman, Favrile Glass. Iridescent glass, patented by Tiffany used to support a crack. in the 1880s,produced by the exposure ofhot glass to Mold-Blown Glass. Glassblown into an open-topped metallic fumes and oxides. mold. Fillet. Thin strip of glass. SeeBorder, Edging Line. Muff Glass. Made by blowing the molten glass into Firing. Proces of heating painted glass so that the the shapeof a cylinder and opening it up to form a flat surface paint and the glass fuse smoothly and se- rectangle. See Crown Glass. curely. Mullion. Vertical stone or wood shaft which divides FIange. The vertical bar of the'H' section of the Lead window Lights. or Came. Width of the flange indicates the size of the Oculus. Circular window with no stone tracery . lead. Opalescent Glass. Glass developed in the late 19th Flashed Glass. A thin, concentrated layer of colored centuty by La Farge and Tiffany, in which streaks of 176 r t i Conservation and Restoration of Stained Glass: An Owner's Guide ~", l'

color, when fused, give a milky, iridescent appear- Scratching. creating highlights with a needle (or ance. similar instrument) by removing portions of paint on Oxides. Metallic oxides used for coloring glass.Added glass not yet fired. See Stickwork. during the fusing process. Color obtained are: blue Seedy Glass.1 Bubbly Antique Glass. from cobalt; red from copper, selenium or gold; Semi-Antique Glass. Hand-blown glass mechani- yellow from lead orchromirim; green from chromium cally fini shed. or copper; violet from manganese or nickel; and Silver Stain. Silvernitrate mixed with gamboge gum. brown or black from manganese or iron. In the fire it stai~sthe surface of the glass a transparent Paint (for glass). A mixture of finely ground glass, yellow color. It is nearly always on the outer surface metallic oxides, and liquid mixing agent, such as of the glass. (Firing range about 1150F.) water or gum arabic, used for painting on glass. It bas Slab Glass. See Dalle De Verre. to be fired forpennanent adhesion. Seealso Enamel, Solder. A mixture of tin and lead that is sweated onto Grisaille and Silver Stain. lead joints of a window. Panel.Unit of stained glass leaded together and made Stenciling. A method of producing a repeated pattern to fit an opening in the Armature. May be of any on glass, frequently used in borders and backgrounds. shape. See Boss, Medallion. Stickwork. Scratching the paint with the handle of Patina. A film produced by chemical action, oxidi- the brush, a stylus or needle before firing in the kiln. zation or sulphurization, during the course of time. See Scratching. Pits. Moles in the surface of the glass, geHerally Stipple. A method of shading, by dabbing a surface circular and beginning as clusters of pinpoints, even- covered with Mat ting with a hard, blunt-ended brush tually enlarging so that they fuse asthe glasscorrodes. before firing, See Badgering. Plating. The placing of one piece of glass of the same Stopgap. The use of old glass from another source to shape on another of different color or texture and fill a missing piece in a window. leading them together for special effect. Also, a Support Bars. Iron bars set in the frame of the method of repairing broken pieces of glass by fit ting exterior of the window, to which the Panels of glass new glass to the exterior face, or sometimes to both are attachedon the inside by Flanges and metal keys. faces, and leading the pieces together. Also called irons and T bars. Saddle Bars are smaller Pot MetaJ. Glass colored in its molten state with bars on the interior of the window tied to the panels by various metallic oxides, so that the color is not con- wires. fined to the surface. See Flashed Glass and Silver Streaky Glass. Transparent glass in which the color Stain. appears as streaks, rather than being uniformly dis- Putty. Material forced between the leading and the persed. . glass to make the window watertight. Tie Wires. Cooper wires soldered to the panel and Quarry .Square or diamond shaped pane of glass twisted around a saddle bar. used parricularly in Grisaille windows. Trace-Line Opaque painted line used for drawing Quill \Vork. Lines of variegated width that are facial features, outlines, etc. scratched in glass paint using a quill. Quill work is Tracery .Ornamental stonework in the upper part of often used to depict haïr. a GOTHIC window with openings for glass. Reamy Glass. Glass with undulating surface show- Vitreous Paint. See Paint. ing the bubbles, striation and ridges fonned in the Wash. A thin coat of paint. process of the blowing. Yellow Stain. See Silver Stain. Ripple Glas~. Machine-rolled glass, the rippled tex- 12 .Resources and Bibliography ture of v.-hich is imprinted from the roller. Sources Rose Window. Circular window with tracery radiat- State Historic Preservation Offices ing in petal-like shapes. to find out where your local office is, contact: Roundel. Circular pane of white glass with a com- The National Park Service plete composition painted on it. See Medallion. u. S. Department of the lnterior Saddle -Bar. See Support Bar . Preservation Assistance Division Sanguine. Reddish-brown paint madefrom hematite, 18th and C Sts., N.W. iron sulphate or sienna. Washington, D.C. 20240

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;:i!I11 Virginia~

(202) 343-9573 ety. 2nd ed. 1985. Available from the New York Landmarks Local Historical Societies Conservancy, 330 W. 42nd St., New York, N. y .lOO3(i. $15 plus $3 postage and handling. to find out where your local office is, contact: Window Rehabilitation: A Manual for Historic Buildings. Pre- The American Association for State and Local pared by the EhrenkrantzGroup. Due late summer 1985. A vailable History from the New York Landmarks Conservancy (address above). 708 Berry Road This book does not deal with stained glass specifically, but may be useful. Nashville, TN 37204 Newton, R.G. The Deterioration and Conservation tif Stained (615) 383-5991 Glass: A Critical Bibliography. London: Oxford UniversitY Consuilant Referral Services Press. 2nd ed., 1982. Highly technical. The National Park Service Regional Offices BulletinoftheAssociationforPreservation Technolo~y, vol. 13, 1981. This entire issue was devoted to glass conservation. to locate your regional office, contact the address SloanJ.L. "Stained Glass Primer" Bistoric Preservatioj1, vol.35, given above no.6. Nov.lDec. 1983. pp. 14 ff. The American Association for State and Local His- Numerous articles on repair and restoration appear in back issues of The Old Bouse Journal, Stained Glass Quarterly, Glass tory Digest, and Professional Stained Glass. to locate those in your area, contact the address The Secretary of the Interior's Standards for Rehabü'itation of given above Bistoric Buildings. U. S. Department of the Interior, 1985. The National Trust for Historic Preservation The Old Bouse Journal Catalog. Published yearly by the Old to locate your regional office, write: House Journal, 69A Seventh Avenue, Brooklyn, N. Y. 11217. Listings of companies and craftspeople. 1785 Massachusetts Avenue, N. W. Washington, D.C. 20036 Selected Bibliography For Historical Research (202) 673-4136 Symbolism in Windows Ferguson,George, Signs and S)-mbolsin ChristianArt.. New York: The American Association of Museums Oxford University Press. 1959. 1055 Thomas Jefferson Street, N.W. Male, Emile, The Gothic Image. New York: Harper & Row 1972, Washington, D.C. 20007 Icon Editions. IN32 (202) 338-5300 The American Experience Sturm, James.Stained Glassfrom Medieval Times to the Present, The Decorative Arts Trust Treasures to be Found in New York. New York: E.P. Dutton, Inc. P. O. Box 1226 1982. (overview) Camden, SC 29020 Connick, Charles J. Adventures in Ught and Color. New York: (803) 432- 7864 Random House. 1937. (Gothic Revival) The Association for Preservation Technology Lloyd, John Gilbert. Stained Glass in America. Jenkentl[)Wn,PA: Foundation Books. The Religious Publishing Comp8l1y. 1963. P. O. Box 2487, Station D (predominantly Gothic RevivaJ) Ottawa, Ontario K1P 5W6 Duncan, Alastair. Tiffany Windows. New York: Silmon and Canada Schuster. 1980. (al1hough this organization is located in Canada, Mckean, Hugh. The "Lost" Treasurers ofLouis Comfort Tiffany. Garden City, NY: Doubleday & Co. 1980. it serves the United States also ) Weinberg, H. Barbara. The Decorative Work of John La Farge. The American lnstitute of Architects New York: Garland Publishing, Inc. 1977. 1735 New York Avenue, N.W. Adams, Henry, and others, John La Farge (exhibitiol11catalog, Washington, D.C. 20006 The Carnegie Museum of Art, Pittsburgh, and the National The American lnstitute of Conservation Museum of American Art, Washington, D.C.) New York: Abbeville Press, 1987. 3545 Williamsburg Lane, N, W . European Imports Washington, D.C. 20008 Harrison, Martin. Victorian Stained Grass. London: Barrie & Jenkings. 1980 (19th century English studios). Haward, Birkin. Nineteenth Century Norfolk Stained Glass. Norwich, England: Geo Books. 1984. Sewter, A. Charles. The Stained Grass ofWilliam Morris and Bis Bibliograhpy Circle. New Haven: Yale University Press. 1973-1974. "How to Choose a Conservator." Pamphlet available from the Aubert, Marcel, and others. Le Vitrail Francais. Paris: Editions Amelican lnstitute of Conservation (above) des Deux Mondes. 1958. Presen'ation Directory: A Listing of Craftsmen. Craftswomen. Contrtrtors, and Professionals. Professionals. Prepared by the New York. Landmark.s Conservancy and the Municipal Art Soci- 78 Conservation and Rcsloration of Staincd Glass: An Owncr'. Guide

*The Census of Stained Glass Windows in America is a not-for-profit organization dedicated to the study, recording and preservation of architectural stained glass in America. To this end it brings together experts from many different fields: craftspersons in the field of stained glass, art historians. museum professionals, and preservation experts.

Roster in 1986 Virginia C. Raguin, Director Paul Norton, Assistant Director: Committee on Conservation and Restoration Art Femenella, Co-Owner, The Greenland Studio. Jane HG)ward, Curator, The Metropolitan Museum of Art, The Cloisters. Michael Lynch, Historic Sites Restoration Officer, State of New York. John Nussbaum, Stained Glass Artist. Virginia C. Raguin, Associate Professor, College of the Holy Cross. Julie Sloan, Preservation Consultant. Robert "~vsocki, Owner, Stained Glass Associates.

Board of Governors Art Femenella, Co-Owner, The Greenland Studio. Alice Conney Frelinghuysen, Assistant Curator, The Metropolitan Mu- seum of Art. Martin Gallin, Gallin & Newman Legal Counsel. Jane Ha!ward, Curator, The Metropolitan Museum of Art, The Cloisters. Michael Lynch, Historic Sites Restoration Officer, State of New York. Hugh McKean, President, The Charles Hosmer Morse Foundation. Paul Nonon, Professor, University of Massachusetts,Amherst. John Nussbaum, Stained Glass Artist. Virginia C. Raguin, Associate Professor, College of the Holy Cross. Julie Sloan, Preservation Consultant. J ames Sturm, Associate Professor, CUNY College of States Island. Kerry Sullivan, Photographic Index, Yale Center for British Art. Catherine Sweeney, Publications Consultant. Robert Wysocki, Owner, Stained Glass Associates.

Board o( Advisors. Madeline Caviness, Professor, Tufts University. Willene Clark, Associate Professor, Marlboro College. Margaret Floyd, Associate Professor, Tufts University. Melville Greenland, Co-Owner, The Greenland Studio. Dwight Lanmon, Director, The Coming Museum of Glass. H. Barbara Weinberg, Professor, SUNY, Queens College.

* Prepared by the Census of stained glass Windows in America 179 Windows by Morgan Studio, New York, Cathedralof the Holy Cross, Boston, c. 1876-80. Bad Iy cracked original glass and 1940s replacements repaired with copper foil technique. Original glass shows back painting {Virginia Raguin)

Detail of enamel painting in heads. Probably Bavar- ian manufacture subcontracted to the Morgan Studio. New York. Cathedral of the Holy Cross. Boston. c. 1876-80. Copper foil repair made in ann. (Virginia Raguin)

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Conservation and Rcsloralion 0: Stained Glass -An Owner'. Guide

3. Raking light on a panel probably of Bavarian manufacture subcontracted to the Morgan Studio, New York. Cathedral ofthe Holy Cross, Boston, c. 1876- 80. Cold paint applied to lower parts of head to left. (Virginia Raguin)

4. This is an overall view of the Hospitalitas and prosperitas window designed by John Lafarge circa 1881 for the Vanderbilt Mansion on 5th Ave, New York. Window measures 1.6mxJm. Extensive use of opalescent glass and pressed gla.rs jewels.

181 ~

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:~1.'-,c'~.! ..~~i :ail ofwindow--,.,~ in fig. 4 This illustrates the painting

.c of La Farge. The vi,reous paint is a reddish 'vn. l1re painted detail on the shield 10 ihe righI of ;igure i~. blue enameL. La Farge regularly applied .:red oil paint onto the glass to modify 1hefinished -.dow.

:..11lof window infig. 4 illustrate.). the use uJ-pressed "'.sjewels in the composition. Eachjewel iswrapped .; U sJIaped lt'ad came. The cames are soldered .:"cher. and all spaces beti1.'een the jewe/s are Jilled 1 solder. 7. Detaii ofwindow in fig. 4. This glass is referred to as 8. Detail of window in fig 4, This illustrates a problem con.;ettior fractured glass. The small, darker bits are common to many windo}\.'s of the American opales- pieces ofmouth-blown glass that arefused to the base cent Era. The glass is a heavily rippled translucent glass during manufacture. This glass was used by type with streaks ofopalescence. Due to inexactchem- Tiffûl:y and La Farge. and tends to be unstable. The istry during manufacture. the glass is inherently shaiowing on the surface is applied glass paint. unstable. The internaI fracturing will continue until the glass deteriorates ta a fine powder.

9. Detc;ii o/reverse side o/window fig. 4. This window was severely deflected (bowing). A/ter flattening, a support systemthin brass fins and heavier steel bars was solderd directly onto the lead cames. This will prevent deflection in the .future but is virtually invisible when viewing the window /rom the obverse side.

lR1 10. T,:is is a photograph ofthe surface of a painted head. Il. Reverseside of a window designed by John La Farge T,:e whitish areas indicate deteriorating paint, a circa 1881for the Vanderbilt Mansion. 5thAve. New c.-"!1nOn problem with Tiffany, La Farge and other York. The panel was dejlected approx. 3 cm in the O;aiescent Era windows. center. Alter jlattening, the intricate fin system was added to prevent bowing in the future.

184 1,.: ~ Conservation and Restoration of Stained Glass -An Owneis Guide ~ ~

12. Window /abricated by the Tiffany studios circa 1905.The Tiffany studios were the originators o/the fin Sllpport system as can be seen in this photo. I

185