0 Gram Number 1919 Caring For Blueprints And Cyanotypes The bright blue blueprint or cyanotypeprocess unframed with other photographic prints. was developed in 1842. It was first used to When blueprints or cyanotypes are made without record herbarium specimens without benefit of a cameras they may also be labeled as photo- camera. The specimens were placed directly grams. These cameraless images are most against sheets of paper impregnated with commonly a ghostly white reproduction of plant chemicals and exposed to light. These specimens or objects on a brilliant blue cameraless images were most common between background-a reverse image of most 1842 and 1860, although some later artists and cyanotypes- housed with photographs or scientists also produced them. scientific illustrations. Between 1880 and the 1920s the process became Both blueprints and cyanotypes are produced popular for producing prints from photographic using light-sensitive iron salts that lodge deep in negatives called cyanotypes (cyan means blue). the uncoated paper. The paper fibers of The most common use of the process occurred blueprints and cyanotypes are visible under between 1890 and the present, when it was used 30.power magnification. Due to their acidic for producing copies of architectural and nature, cyanotypes and blueprints are frequently engineering drawings, called blueprints. Many brittle and may have some brown staining, or architects of the last hundred years used foxing, that results from mold growth around blueprints to reproduce their working drawings, minute metal particles in the paper. Despite and many amateur and professional these problems, blueprint and cyanotype images photographers used cyanotypes to produce draft are usually stable and can maintain a surprisingly copies of photographic prints. bright image. Appearance and Deteriomtion Blueprint and cyanotype images commonly fade when: Both blueprints and cyanotypes have bright blue image detail with white highlights on smooth l placed in an alkaline (buffered) environment. matte-surfaced uncoated paper. However, if the An alkaline or buffered environment causes images were photographically reversed, they blueprints and cyanotypes to lose image detail may have white image detail with blue and density. The images first turn yellowish- highlights. These reversed images are brown before eventually fading to white. sometimes labeled with their alternative names ferroprussiate prints or pellet process prints or l exposed to light. Original blueprints and the technical process name photogram. cyanotypes should not be used in exhibitions. Blueprints most often reproduce architectural or NOTE: Surprisingly, images that have faded or engineering drawings, diagrams, and plans. lost image detail due to light exposure can They are often discovered in construction files, recover image density over time if they are oversized map cases, and maintenance records. stored in the dark in a neutral, non-buffered. Cyanotypes are photographs usually housed environment.
National Park Service Conserve 0 Gram 19/9Housing Blueprints and Cyanotypes plastic sleeves or folders, including polyester. Polyester sleeves or folders are recommendedSince blueprintsand cyanotypescan be damaged only if the cyanotype or blueprint is not brittleby both light and an alkaline environment, but is experiencing fading due to contact withblueprintsand oversize cyanotypesshould be buffered or alkaline materials from which ithousedflat in unbuflered, neutral-pHfolders, cannot otherwise readily be separated.withinmetal map cases or withinshallowsolander-typeunbufered boxes. Cyanotypes that Handlingare 8” x 10” or less may be housed upright ontheir edge within an unbuffered, neutral-pH four- All folders within a drawer or box should be theflap sleeve, then in an unbuffered folder, and same size, regardless of the size of the blueprintfinal1y in boxes like other photographs. Use or cyanotype in them. This procedure will keepunbuffered folder stock that is high alpha smaller folders from shifting to the back of thecellulose and low-lignin. map case or box and getting lost or crammed together. Each folder should be carefullyBecause of their brittleness, blueprints and labelled near its fold in pencil with the collectioncyanotypes tear easily. Each blueprint or name, box or drawer number, accession/catalogcyanotype should be housed in its own individual number, other identifying number, photographerfolder that is unbuffered, high alpha cellulose, or artist, subject, date, and any restrictions-and low-lignin. If, for reasons of economy, this particular! y those related to fragility.is not possible, use unbuffered neutral-pH tissuepaper to separate individual images from each Since blueprints and cyanotypes lack mechanicalother and from their folder. Never use strength, they must not be bent, folded, rolled,buffered, glassine, or ground wood housing or moved without a rigid support. Therefore,matetis. Avoid placing more than three researchers and staff must remove a folderoversize items in a folder because of their completely from a map case drawer or boxfragility. Rolling blueprints or cyanotypes on before opening the folder to view an item.tubes is discouraged because of their brittleness When removing a single folder from a drawer orand lack of durability. If rolled they tend to box, support the folder with a piece of acid-freecrack and tear. unbuffered board.If blueprints to be rehoused are already rolled or Riffling through folders in a map case or box byfolded you must flatten and unfold them onZy if bending the folders back upon each other canthey are strong and durable. Brittle or fragile also damage the images. Consider storingitems should be flattened or unfolded by a folders in a map case with their labeled spinesconservator. (See Conserve 0 Gram 13/2, How (i.e., the fold portion of the folder) facing theto Flatten Folded or Rolled Paper Documents.) drawer front to discourage browsing. All staff should be warned not to fold or bend thesePlastic Sleeves and Encapsulation images towards the back of the drawer to speed browsing. Instead, remove the images from thePlacing the highly acidic blueprints and drawer in their folders.cyanotype images in a microenvironment thattraps the acid next to the paper enhances the Researchers and staff who work with oversizepaper’s brittleness. However, pal yester sleeves blueprints and cyanotypes require a large cleardo have the advantage of limiting contact with an work space. The table must be big enough toalkaline environment, thus discouraging image allow three stacks of folders as well as a writingfading. Generally avoid encapsulating brittle surface: one stack contains the folders alreadyblueprints or cyanotypes or housing them in any viewed; a second stack contains the folders to Caring for Blueptints and Cyanotypes
Conserve 0 Gram 19/9 National Park Service be viewed; and the third stack is the folders References being viewed. Coe, Brian and Mark Haworth-Booth. A GuideBlueprints or cyanotypes that have original to Early Photographic Processes. London:notations or changes by the image creator or the Victoria and Albert Museum, 1983.image creator’s staff are commonly treated asoriginal records. Such original notations on Reilly, James M. Care and Identijkation ofblueprints are relatively common with working 19th Century Photographic Prints. Rochester,drawings. Many blueprints or cyanotypes have NY: Eastman Kodak Publication No. G-2s,outlasted the original negative or drawing upon 1986.which they are based, making them the lastrecord of an image. Last surviving copies Ritzenthaler, Mary Lynn, Gerald J. Munoff,should be treated as originals. Margery S. Long. Archives and Manuscripts: Administration Photographic Collections. of Sources SAA Basic Manual Series. Chicago: Society of American Archivists, 1984.Unbuffered, pH-neutral folders and folder stock;storage boxes and solander-type boxes; and Wilhelm, Henry. ;Ihe Permanence and Care ofunbuffered, pH-neutral tissue paper are available Color Photographs: Traditionaland Digitalfrom archival-quality materials suppliers, such as Color Prints, Color Negatives, Slides, andthe following: MotionPictures. Grinnell, Iowa: Preservation Publishing Company, 1993.Conservation Resources International, 8000-HForbes Place, Springfield, VA 22 151;(800) 634-6932 or (703) 321-7730;Fax (703) 32 l-0629.Light Impressions Corporation, 439 MonroeAvenue, P.O. Box 940, Rochester, NY 1460300940; (800) 828-62 16 or (7 16) 27 l-8960;Fax (7 16) 442-73 18. Diane Vogt-O’Connor ArchivistUniversity Products, 517 Main Street, P.O. Box Curatorial Services Division101, Holyoke, MA 01041-0101; (800) 628-1912 National Park Serviceor (413) 532-943 1; Fax (800) 532-928 1. Washington, DC 20013-7127 .The Conserve 0 Gram series is published as a reference on The series is distributed to all NPS units and is available to non-NPScollections management and curatorial issues. Mention of a product, institutions and interested individuals by subscription through thea 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) 5 12-2233. For furtherPark Service. Sources named are not all inclusive. It is suggested information and guidance concerning any of the topics or proceduresthat readers also seek alternative product and vendor information in addressed in the series, contact the NPS Curatorial Services Division,order to assess the full range of available supplies and equipment. P.O. Box 37127, Washington, DC 20013-7127; (202) 343-8142.Caring for Blueprints and Cyanotypes 3