0 Gram

Number 14/2

Storage Enclosures For Photogra&ic Prints And Negatives

Storage enclosures for photographic prints and The quality of used to make is also negatives are available in a variety of materials important. Groundwood, from which many and formats. One must decide between paper or modern are made, contains lignin that plastic, buffered or non-buffered paper, poly- produces acids rapidly. Papers described as ester or other plastics, sleeves or . Zignin-flee are produced from cotton or linen Choosing the proper enclosure requires a know- (containing little lignin) or have had the lignin ledge of the alternatives. This Conserve 0 chemically removed. Lignin-free buffered and Gram reviews the various options, discussing non-buffered (neutral) paper enclosures are advantages, disadvantages, and special pre- available. cautions for each. Whatever enclosure is chosen, avoid handling photographic prints and The effect of direct contact of buffered paper on negatives with bare hands. Oils and perspiration photographic emulsions is presently being ques- can damage emulsions. Lint-free gloves are tioned. Buffered storage enclosures are not rec- available from conservation or photographic ommended for color images, cyanotypes, or suppliers. albumen prints. They are recommended for cellulose nitrate and early safety film negatives, All enclosures used to house photographs should brittle prints, and photographs on brittle acidic meet the specifications provided in the American mounts. Research has yet to be conducted to National Standards Institute (ANSI) Standard IT determine the effect of buffering agents on many 9.2- 199 1. l The standard provides specifications photographic processes; however, if the relative on enclosure formats, papers, plastics, humidity of the storage environment is below adhesives, and printing inks, and requires a 50%, buffered enclosures should present few, if variety of enclosure tests. any, problems. When in doubt, the use of neu- tral enclosures is probably advisable. Paper Mhrterials Research has demonstrated that even archival The term acid-free is widely used to refer to papers may be harmful to the photographic archival-quality paper materials constructed of image. Labels such as acid-free do not guar- either neutral or bu$fk-ed paper. A more precise antee that a material is safe when used with distinction should be made between the two. photographs. The only way to be certain of Neutral enclosures, constructed of paper in the photographic inertness is to have materials un- neutral pH range (7.0-73, do not contain acids dergo the Photographic Activity Test (PAT) as that will damage photos stored in them, but have specified in ANSI Standard IT 9.2. The PAT a limited capacity to absorb acids from the has two components: a test to detect image environment or from the objects stored inside. fading resulting from harmful chemicals in en- Buffered paper enclosures (approximately pH closures, and a test to detect staining reactions 8.5) contain an alkaline material that can serve between enclosures and gelatin. Consumers to neutralize acids as they form. should contact archival suppliers to see if their National Park Service Conserve 0 Gram 14/2

products comply with ANSI IT 9.2, and have the image. When storing photographs in seamed passed the Photographic Activity Test.2 envelopes, the photograph should be inserted .---, with the emulsion away from the seam. When PAT test results are not available, pur- chase materials from suppliers familiar with the Seamless Paper Envelopes. A seamless enve- special needs of photographs, and choose enclo- lope does not have any adhesive. The sures which are lignin-free, 100% rag, and not is formed with three or four flaps which fold highly colored (especially avoid black). over to produce a pocket. The fourth flap, if enclosures are not recommended. present, closes the envelope completely, protect- ing the object within from dust and dirt. The Advantages and Disadvantages of Paper construction of this envelope encourages the user to place the object on a flat surface to open it, 1. Paper enclosures are opaque, protecting the which can be an advantage for brittle or fragile object from light. However, this makes items such as glass plate negatives. Also, this viewing difficult, requiring the removal of the type of enclosure is constructed so that it can object from the enclosure. This increases compensate for the thickness of an object. damage from handling, abrasion, and finger- printing, especially in heavily used collec- Paper Folders. A folder is a sheet of paper that tions. is folded in half. It is closed on one side only and must therefore be kept in a properly fitted 2. Paper enclosures are porous, protecting the box in order to effectively hold the image. If object from the accumulation of moisture and used for vertical storage in files, the photograph detrimental gases. This is especially impor- stored inside must be well supported to prevent tant for cellulose nitrate and early safety film sagging or curling. Folders are simple to make negatives where the gases generated by the and are very useful for large or mounted items. deterioration of the support material are harmful to the image. Plastic Materials

3. Paper enclosures are generally less expensive Plastic enclosures of archival quality may be than plastic enclosures. made of polyester, polypropylene, or polyethyl- ene. They should not be coated or contain 4. Paper enclosures are easy to write on. plasticizers or other additives. Polyester is the most inert and rigid of the three. It generates Seamed Paper Envelopes. An envelope is an static electricity that can attract dust, and it is enclosure with one open end; it may or may not expensive. Polyester enclosures should be either have a protective top flap. The seam in paper DuPont Mylar@ D or ICI Melinex@ #5 16. Poly- envelopes should be located at the sides and propylene is almost as rigid and strong as poly- across the bottom. Any adhesives used in con- ester when in sleeve format, but is soft when struction should be non-acidic and unreactive used for ring binder storage pages. Polyethylene with silver. Most envelopes come with a thumb is the softest, most easily scratched, and least cut, but those without are preferred. Thumb rigid of these plastics. cuts allow air to touch the photo, and encourage users to grasp the photo and pull it from the Plastic enclosures made from polyvinyl chloride sleeve. [Rather, to remove a photo, squeeze in (PVC) are unacceptable for archival photo- slightly on the edges of the envelope, and tap the graphic storage. This plastic, often referred to photo out, handling only the edges.] A top flap as vinyl by suppliers, is not chemically stable may be desirable in order to prevent dust from and will cause deterioration of a photograph over entering the envelope and causing abrasion of time.

2 Storage Enclosures for Photographic Prints and Negatives Conserve 0 Gram 14/2 National Park Service

[NOTE: Plastic enclosures should only be used Plastic Folders. These are usually made from for objects that are stored in a climatically con- polyester. They may be successfully used in trolled environment because these enclosures can conjunction with paper envelopes, the polyester trap moisture. See number 3 below.] folder protecting the image from handling when- ever it is removed from the envelope. Advantages and Disadvantages of Plastic L- Velopes. TH These are a combination envelope- 1. Plastic enclosures have the great advantage of folder, being an envelope sealed on only two allowing an image to be viewed without re- adjacent sides. This allows for easy insertion moving it from the enclosure. This greatly and removal of objects, but provides more sup- reduces the chance of abrading, scratching, or port than a folder. This format is particularly fingerprinting the photograph especially in useful for smaller format images. heavily-used collections. Plastic Sleeves. A sleeve is an enclosure open at 2. Moisture and sulphides in the environment two opposite sides. It can be made from poly- react with photographs and hasten their dete- ester or polypropylene. Usually, these sleeves rioration. Plastic enclosures protect the ob- are a one-piece construction with a self-locking ject from the atmosphere and prolong the life fold on one edge. This fold provides for easy of the image. There are two important ex- insertion and removal of the photograph without ceptions: cellulose nitrate film and early abrading the image on the sharp edge of the safety film should not be stored in plastic enclosure. enclosures. Such enclosures accelerate their deterioration by trapping harmful gases. Polyester Encapsulation. Polyester encapsula- tion encloses a photograph between two sheets of 3. Plastic enclosures can trap moisture and cause polyester, sealed on all four sides with either L- ferrotyping (sticking with resulting shiny double-sided tape or a special polyester welding areas) of the image. This is a particular machine. Encapsulation provides physical sup- threat in storage environments with high port and protection from the environment. It is relative humidity or in the event of a disaster useful for storing fragile prints, especially those involving water. which are torn. Encapsulation is not recom- mended for photographs adhered to poor quality 4. Plastic enclosures with matte or frosted sur- mounts or for contemporary color photographs. faces are not recommended, as they can be [See Conswve 0 Gram 1313.1 abrasive and may scratch the emulsion. Ring Binder Storage Pages. These pages are 5. Plastic enclosures can be difticult to write on. made to fit three-ring binders with slipcases. They are available in a wide variety of formats, 6. Plastic enclosures can be tlimsy and may re- sizes, and materials, including polyester, poly- quire additional support, such as archival- propylene and polyethylene. They are an excel- quality Bristol board. Any information which lent alternative for small, concentrated collec- should accompany the image can be recorded tions of uniform size. on this board. Polyester Sheet - Matboard Folder. These Plastic Envelopes. Plastic envelopes normally folders are made of a sheet of polyester and a have heat-sealed seams, which eliminate any sheet of matboard of the same size, attached potential problem with adhesives. Both polyeth- together along one long edge with double-sided ylene and polyester envelopes have been market- tape. The matboard gives needed support and ed by conservation product suppliers. the polyester allows the image to be easily

Storage Enclosures for Photographic Prints and Negatives 3 Natiod Park Service Conserve 0 Gram 14/2 viewed. These folders should be stored flat. Notes They are particularly useful for storage of over- sized photographs or photographs on rigid 1. ANSI IT 9.2-1991. “American National Standard mounts. for Imaging Media - Photographic Processed Films, Plates, and Papers - Filing Enclosures and Polyester Sheet Within a Paper Folder. This Storage Containers, ” New York: American National Standards Institute, 199 1. enclosure consists of a paper folder with a poly- (11 West 42nd Street, New York, NY 10036) ester sheet attached along an inner edge, oppo- site the center fold. The attachment is made with 2. This test can be performed by Image Permanence double-sided tape. The polyester holds the Institute, Rochester Institute of Technology, F. E. object in place and protects it from dirt and Gannett Memorial Building, P.O. Box 9887, handling, but allows for easy viewing and Rochester, NY 14623-0887. removal. The paper folder provides support to the image and protects it from light. These folders are especially useful for small fragile prints. Gary Albright Senior Photographic Conservator Summary Northeast Document Conservation Center 100 Brickstone Square Andover, Massachusetts 01810-1494 Many of the enclosures available for photo- graphic storage have been discussed in this Formerly issued us Conserve 0 Gram 146. Reprinted with Conserve 0 Gram. Each has been discussed permission of the Northeast Document Conservation Center individually, but often two enclosures can be (revised 8192). Refer to NPS Tools of the Trade for a combined to form another format with its own listing of many of the enclosures discussed in this characteristics. An example would be the use of Co,rzserve 0 Grurn. NPS Curatorial Services Division, Harpers Ferry, WV 25425, (304) 5356072, can provide polyester folders within seamed paper envelopes. Parks with additional source information. Enclosures arc Each of these systems has advantages and also available through suPpliers of archival quality disadvantages. The final choice of enclosure materials. Consult manufacturer or vendor to ensure that will depend on the particular needs of a Products meet recommended guidelines. collection.

The Conserve 0 Gram series is published as a reference on The series is distributed to all NPS units and is available to non-NPS collections management and curatorial issues. Mention of a product, institutions and interested individuals by subscription through the a manufacturer, or a supplier by name in this publication does not Superintendent of Documents, U.S. Government Printing Office, constitute an endorsement of that product or supplier by the National Washington, D.C. 20402, FAX (202) 512-2233. For further Park Service. Sources named are not all inclusive. It is suggested information and guidance concerning any of the topics or procedures that readers also seek alternative product and vendor information in addressed in the series, contact the National Park Service, Curatorial order to assess the full range of available supplies and equipment. Services Division, Harpers Ferry, WV 25425, (304) 535-6410. 4 Storage Enclosures for Photographic Prints and Negatives