Monday, May 11, 2020

Preservation Resources for Paper and Photo Collections

Thank you to everyone who joined us on Friday for the Preserving Paper and Photo Collections Facebook Live. You can check out the video on the Schenectady County Historical Society’s Facebook page, under “Videos.” This blog post complements that video by providing a few more details as well as links to further resources.

The goal of preservation is to extend the lifespan of historic and archival materials by mitigating the factors that cause deterioration. The main cause of deterioration is acid, and other factors include light (especially UV light), improper or excessive handling, high temperatures and humidity, fluctuations in environment, pests, mold, water, and fire.

Basic rules for preserving paper and photo collections:
  • One of the golden rules of archiving is to never do anything that is irreversible.
  • Do what you can. Don't be overwhelmed by the process, the cost, or the idea of doing it 'exactly right.'
  • Label as much as you can, especially on the outside of enclosures (e.g. folders and boxes). Try to answer the five W questions. Putting this information on the label will make it easier to organize your collection and reduce the amount of handling you'll need to do in the future.
  • Keep like with like. Organize your materials by type and by size to maximize your supplies and storage.
  • Remove fasteners like rubber bands, paper clips, and staplers. These will damage your materials over time; causing weak points, discoloration, and rust transfer.
  • Find the 'goldilocks' level of fullness for your boxes (i.e. a box that is not too full or too empty). A box that is too full will put uneven pressure on the materials inside and require some force to get documents from it, while a box that doesn’t have proper support will cause documents and photos to bend and warp.
Key terms:
  • Encapsulation -- A conservation treatment where an original item is housed in an enclosed archival plastic envelope; not the same as lamination or sleeving. Learn more:
  • Enclosures  -- A container used to store materials. Examples of enclosures include sleeves, boxes, canisters.
  • Lignin -- A molecule found in wood-pulp paper. It plays an important part in binding cellulose molecules together, but it also releases acid when it breaks down.
  • P.A.T. Passed -- Photographic Activity Test is a standard procedure (ISO 14523) to check for potential chemical reactions between materials used to make enclosures and photographs stored in those enclosures. Enclosures that carry the label "P.A.T. Passed" are considered stable and are recommended for archival storage, especially photos and photographic films.
  • Acid-free or acid neutral -- Material, usually paper, with a pH of 7.0 or greater when manufactured. Acid-free papers are distinguished from papers that contain a residue of the acids used to break up wood fibers during manufacture. The residual acid continues to attack the paper fibers, making the paper brittle over time. Archival papers are typically made from alpha cellulose, are lignin free, and often contain an alkaline buffer to counter any trace of acids used in processing or environmental acids.
  • Buffered -- A buffer is a solution that can neutralize acid. Enclosures that have been treated with an alkaline solution made from calcium carbonate or magnesium carbonate to compensate for residual manufacturing acids or from acidic environmental contaminants.
Basic rules for storing materials:
  • Store materials in a cool, dry, dark place with stable temperature and humidity. The ideal is a temperature between 65-70 degrees and humidity between 35-50%, but stability is definitely key.
  • Avoid storing your collection in basements, attics, or garages. 
  • Dust your storage space regularly, including the outsides of boxes. 
  • Think carefully about the enclosures you use for your collection. Folders should be acid free and buffered. Use cardboard boxes instead of plastic tubs. Purchase supplies that match the size of your materials (e.g. legal-sized folders for documents that measure between 11 to 13.5 inches long). Folders and sleeves should be longer and wider than the items inside them and items should fit comfortably without folding. Folders and sleeves should fit snugly inside of boxes.
  • Plastic, transparent sleeves (e.g. polyethylene sleeves) should be for materials that you plan to use or display often so you don't need to remove them from their enclosures or handle them directly. Not all plastics can be safely used. You might have figured this out the hard way when opening an old photo album only to find the plastic brittle, yellowed and sticking to the photos. The types of plastics that you want to look for are polyester, polypropylene and polyethylene.
  • When planning enclosures, measure three times. Measuring at multiple points ensures precision and will help you choose the correct enclosure.
  • Most materials can be stored vertically inside folders and boxes. Large or heavy items should be stored horizontally to prevent them from curling or squishing under their own weight.
Safe handling:
  • Gloves or no gloves? For most archival materials, clean, dry hands are more appropriate than gloves. Photographic materials, metals, and some fragile materials should be handled with gloves. Gloves can be cotton, latex, or nitrile. Latex and nitrile gloves should be the powder-free kind. Read more about the use of gloves in archives:
  • Don't eat or drink while working with materials.
  • Avoid wearing scents, lotions, and hand sanitizers.
  • Make copies of fragile materials so you don't need to handle the originals directly.

Common preservation supplies:
  • Pencils --  Avoid using pens or ink on archival materials or when working with archival materials. Soft lead pencils work best. 
  • Photo marking pencil -- never mark your photos on their faces. In many cases, you can label photos on the back with a regular soft lead pencil, but you may need a photo-marking (e.g. Stabilo-All pencil) pencil to mark photos with coatings.
  • Boxes
  • Folders
  • Sleeves
  • Copy paper
  • Unbuffered tissue paper
  • Tweezers
Vendors for supplies:

Common preservation concerns:
  • Newsprint -- Newsprint, which must be produced as economically as possible, has more lignin in it than finer papers. At the mill, the wood that will be turned into newsprint is ground up, lignin and all. Lignin eventually turns paper yellow because of oxidation. The lignin will absorb more light, giving off a darker color. If newsprint were kept completely out of sunlight and air, it would remain white. After only a few hours of sunlight and oxygen, however, it will start to change color. Make copies of newspaper clippings and store them separately from the originals. Any materials that are stored with newsprint will absorb acid from the newsprint and will deteriorate faster. Once copies are made, you can choose to discard the newsprint original or store it in a folder away from light and heat. Learn more:
  • Smells -- First, be sure the smell is not the result of an active problem (e.g. mold) and that materials are stored in an appropriate location. There may not be a way to remove the smell completely, but using dryer sheets (without dyes or fragrances), baking soda sachets, activated charcoal sachets, or unscented clay kitty litter can clear up most of the problem. Learn more:
  • Rolled or folded items -- Folds and rolls cause weak points where your documents or photos will eventually break. It's best to store materials flat, unfolded and unrolled, whenever possible. There are a couple of techniques to help with unfolding, unrolling, and flattening. The least technical is to use weights to gradually flatten the item. You should avoid folding or rolling in the opposite direction as this will stress weak points and may cause breaks. Learn more:
  • Fragile items -- Items that are torn, brittle, very old, and made of thin or delicate materials require extra care when storing and handling. Make copies so you won't need to handle originals except for special occasions. Use sturdy mats and folders to provide structure and support in storage. Consult with a conservator about options for repairing or stabilizing fragile items. Never use tape or glue on original materials. Learn more:
  • Displaying items -- Items may be displayed, but should be placed away from direct sunlight and heat sources. Items on display should be rotated so that they get a break from the stress of being on display. You may want to create a high quality copy for display instead of using the original. Learn more:
  • Insects and other pests -- Depending on the type of pest and the size of the problem, you may need to consult a professional exterminator and/or conservator. Focus on resolving the source of the problem, creating a safe storage environment, and preventing future damage. In many cases, pest damage is not reversible, but light cleaning may help remove debris and discoloration caused by pests. Learn more:
  • Nitrate film -- Nitrate film was manufactured between 1890 and 1951. It is extremely dangerous and should not be stored in your home. Its gases are toxic and combustible. If you have nitrate film, you really need to find a home for it at a repository with proper cold storage facilities or properly dispose of it. Learn more:

Links to further resources:

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