Judging Permanence for Reformatting Projects: Paper and Inks
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ConserveO Gram September 1995 Number 19/14 Judging Permanence For Reformatting Projects: Paper And Inks Many permanently valuable NPS documents fibered, high alpha-cellulose cotton and linen such as correspondence, drawings, maps, plans, rags. Early rag papers were strong, stable, and reports were not produced using permanent and durable with relatively few impurities. and durable recording media. When selecting In the mid-17th century, damaging alum paper items for preservation duplication, items sizing was added to control bacteria and marked on the list below with a " - " are at mold growth in paper. By 1680, shorter highest risk and should have special priority for fiber rag papers were being produced due to duplication. Document types marked with a the use of mechanical metal beaters to shred "+" are lower priorities for reformatting as they the rag fibers. By about 1775, damaging tend to be more stable and durable. See chlorine bleaches were added to rag papers Conserve O Gram 19/10, Reformatting for to control the paper color. Acidic alum Preservation and Access: Prioritizing Materials rosin sizing was introduced around 1840 to for Duplication, for a full discussion of how to speed the papermaking process thus leading select materials for duplication. NOTE: Avoid to even shorter-lived papers. Rag papers using materials and processes marked " - " when became less common after the introduction producing new documents. of wood pulp paper around 1850. Compared to rag paper, most wood pulp papers have Paper much poorer chemical chemical and mechanical strength, durability, and stability. All permanently valuable original paper - documents should be produced on lignin-free, Ground or mechanical wood pulp paper: high alpha-cellulose papers with a pH between After 1850, most paper produced was 7.5 and 8.0, specifically those papers meeting machine-made paper with a high proportion the American National Standards Institute of short-fibered and acidic wood pulp. (ANSI) Standards 1 for permanent records. Machine-made paper has a distinct grain and Below is a brief overview of the types of paper will tear or fold easily along the grain. found in original documents: Ground wood pulp papers are unstable and have a high lignin content. High lignin + Handmade paper: Most paper was hand papers, even when buffered, have a short life made before the mid-1800s. Early hand and less strength. Lignin is light-sensitive, made paper often has longer fibers, a water and breaks into acidic compounds as it ages. mark, and no pronounced grain direction that The use of additives, such as alum rosin makes it more likely to tear or fold in one sizing, bleach, sulphur dioxide, and others direction than in another. Handmade paper has made the paper significantly more acidic. often has one or more deckled (feathered) Acidic paper lacks strength and can become edges. Before 1850, most Western paper very brittle. Contemporary ground wood was made out of cotton or linen rags. pulp paper has a life of 50 years or less. Most contemporary paper used for + High rag content paper: Before the mid- correspondence, reports, and publications is 17th century, paper was made of long- ground wood pulp paper. National Park Service Conserve O Gram 19/14 Recycled paper: Although admirable + Graphite or "lead" pencils: A natural fonn - environmentally, recycled paper has not of carbon, graphite is stable, but prone to proven reliable for paper records of lasting smearing, like all friable media. value. Neither strong nor durable, recycled paper has very short fibers, bleaches and + Carbon inks: Widely used until the 19th additives, and very little strength. Since the century, purely carbon inks are permanent beginning of papermaking, paper has been and non-damaging to paper. Relatively recycled; however, it only has been a major unaffected by light, carbon pigments are still commercial endeavor for the last 20 years. available today for calligraphy and drawing. + Buffered papers: Any sort of paper can be Iron gall inks: Widely used to write on buffered, from strong and durable rag papers - parchment and vellum papers, acidic iron to weak and brittle wood pulp papers. gall inks were common during the 17th-19th Buffering is the addition of an alkaline centuries. Acidic iron gall inks may produce reserve, usually calcium carbonate, to paper. a lace or stencil effect by actually eating into The alkaline reserve gradually depletes over the paper until the actual sketch or words are time. Adding buffering does not strengthen eaten away, leaving a stencil. These inks or lengthen short paper fibers or remove were frequently used in fountain pens in the damaging lignin from paper. Buffering 1860s and for letterpress copy books in the absorbs and neutralizes acids. Inappropriate 1870s. Copy these documents after buffering can damage some materials that are stabilization by a conservator. naturally acidic. For example, deacidifying acidic blueprints and/or cyanotypes or even Felt and fiber tip marker inks: Commonly placing them next to buffered paper can - available since the 1960s, these water and cause image fading. solvent soluble inks are prone to washing off if exposed to water and are quite light Select neutral pH materials if the use is sensitive. Permanent versions of these pens uncertain. Longer fiber papers, like rag may be quite acidic. papers, have significantly more strength than wood pulp papers, which have shorter fibers. Aniline dye inks: Commonly available since Ground wood pulp papers with a high lignin - the 1860s, acidic and impermanent aniline content, despite buffering, will have a dye inks appear in many fountain pen inks. relatively short life. Do not apply spray deacidification solutions to materials without Ballpoint pen inks: First developed around talking to a conservator. Do not - 1930, ballpoint pen inks have changed over automatically place buffered paper next to time from dyes dissolved in oil to glycol inks acidic materials without determining if the in solvent or water. These materials vary media will be damaged. See the Museum greatly in life although they are generally Handbook, Part I, Appendix J for further quite water-soluble. guidance. + Typewriter inks: During the last century, Inks, Dyes, Graphite, Pigments and Toners typewriter inks have been composed of a wide variety of dyes, pigments, solvents, and To be permanent, colorants and binders of inks, other substances. Varying in life and dyes, pigments, and toners should contain permanence, self-correcting typewriter carbon black or inorganic colored pigments and ribbon inks tend to be the least permanent of stable resins (for example, stable forms of these media. polyesters, polymides, acrylics, phenolics). Printing and machine copying must produce + Laser printer toners: Available for the last strong bonds between inks or toners and paper 20+ years, laser printer inks are stable, as surfaces. long as the printer is properly adjusted so 2 Judging Permanence for Reformatting Projects: Paper and Inks Conserve O Gram 19114 National Park Service that the toner fuses. NOTE: National Letterpress copy papers: Letterpress copy Archives and Smithsonian Institution studies - papers are thin, overbeaten papers that indicate that toner fusing should be tested by produced copies when used as blotters running a white glove over the document. If against freshly inked surfaces. Letterpress the glove shows any darkening because of copies have surprising mechanical strength toner, the toner is not fusing properly and for their thinness. However, since acidic the printer requires adjustment. iron gall ink was frequently used to make the copies these copies are often in poor + Dot matrix printer ribbons: Available for shape. They may look like stencils when the last 30 years, dot matrix printer ribbon the acidic ink has eaten away the paper. produced documents are generally long-lived Letterpress copies were produced during the and stable. Their life is equivalent to that of 17th-20th centuries, although they have carbon copies. They are the only stable become quite rare in the latter part of the choice if an impact printer is needed to 20th century. produce carbon duplicates. Carbon paper copies: First developed in Daisy wheel printed documents: Commonly - the 1870s, carbon papers are still used in - available for the last 35 years, daisy wheel typewriters to produce impact copies today. printed documents are short-lived and Carbon copy paper has been produced using unstable media not recommended for a variety of media including carbon black archival storage. with oil and naphtha; coal tar dyes in wax or oil; and mineral oils and similar Ink jet documents: These water-soluble, materials. Paper bases for these mixtures - short-lived media produce documents that have varied widely from excellent to poor. smear and run easily. They have been commonly available during the last quarter Carbonless copy papers: These non of the 20th century. NOTE: It is - permanent papers utilized a wide variety of anticipated that pigments will be available pressure and chemical systems to form copy within a year for use in ink jet printers. images. These processes have been Using pigments instead of dyes will produce common in the latter half of the 20th long-lived documents. century. Ink pad ink: Most ink pad ink is not long + Gelatin dye transfer copies: These stable - lived, although the concept of an ink pad is photographic copies, sometimes called centuries old. The Library of Congress Verifax copies, were commonly produced provides quality permanent and durable on uncoated paper between 1952 and 1976. stamp pad/pen ink. NOTE: This ink is the Their life is partially determined by their best and most permanent ink available. paper quality which ranged from excellent Write the Library of Congress, National to very poor. They range in tone from a Preservation Program, LMG21, Washington, deep gray to a warm brownish tone. DC 20540 for a brochure and ordering information. Thermographic copies: Developed around - 1950, these heat-sensitive papers are Common Copy and Duplicate Paper exposed to strong light during the Document Technologies production process.