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While attempting to recover the past through genealogical research we may sometimes fail to preserve the present. This article may inspire you to trade in your shoe box of photographs for a preservation system that will reflect the value of some of your irreplaceable artifacts.
Generally, our photographic collection will be an emulsion applied to a clear substrate -film. This emulsion could be a positive image such as a 35mm slide (what you see on the film looks like what you see with your eye), or a negative image, which becomes positive when it is printed from negative film to the photographic paper we put in our picture albums.
If you have a photograph you may also have the negative from which it was made. This would give you an automatic backup if a negative or print were destroyed. If you start with a slide, however, that piece of film is the only record of the image.
To protect photographic slides and make them accessible for viewing, it is common practice to insert them into slide pages which can be placed into a 3-ring binder or other filing system. Slide pages, especially those made before 1985, are commonly made of polyvinyl chloride (PVC). This plastic emits a gas which will lift the photo emulsion from its film base. To check for this problem, remove one of your slides from its sleeve and hold the page up to the light. If you see remnants of the image on the plastic page, the page is probably made of PVC. Replace the slide page with one labeled "archival", or known to be made of polyester (mylar), polypropylene, or polyethylene.
Everything said about slide pages also applies to negative pages (which hold the cut negative strips from which prints are made). Negatives are also stored in sleeves made of paper (which should be archival, acid free paper). Do avoid negative sleeves made of acetate.
When storing slides, cabinets made of bare or ordinarily painted wood can give off harmful vapours. Better to choose cabinets made of metal with baked on enamel or polypropylene boxes.
Now we consider the common photograph. The image we want is printed on paper. The photograph is often then mounted on paper for purposes of filing and viewing. Since the whole media is based on paper, paper as a topic deserves some special consideration. The longevity and durability of paper has been of particular concern during the past two decades. Many books and documents have not only yellowed with age, but the paper itself has been self-destructing. What is happening and how can we archive paper items when permanence is important?
Acid is the greatest enemy of well-stored paper. Paper is made from cellulose (plant) fibers matted together to form a sheet. Acid will attack the interlocked fiber strands, causing them to "unlock" or break apart. The paper disintegrates.
Acid development within paper can come from two sources. First, from the plant fibers themselves. Tree-like plant cells grow upright because of a "glue" that occurs between the plant cells. This glue, called lignin, allows the cells to grow vertically rather than as limp spaghetti. After the plant has died lignin becomes quite acidic. Any paper made from a tree or "woody" plant will acidify and degrade if the lignin content is not removed or neutralized before paper formation.
The second source of acid within paper is from chemicals and materials added during the paper making process. An example is the addition of Aluminum Sulphate or "alum" to some papers to give the paper resistance to the penetration of inks. The sulphate portion of alum can attach itself to humidity absorbed from the air and it becomes sulphuric acid!
In addition, atmospheric pollutants can react with chemicals added to paper pulp and generate acidic content. So even if a paper is listed as "acid free" or "ph neutral" as it comes from the mill, it may not remain that way.
A chemical "buffer" can be added to the paper to neutralize acid as it develops. This will extend the life of the paper, but a buffer is finite and will, over time, be exhausted. (Buffering chemicals also attack the dyes in colors prints and may not be the best choice for a mounting surface).
Some plant fibers have a naturally low lignin content and are quite resilient and resistant to degradation even if they do become acidic. Cotton fiber is an excellent example. It contains no lignins and is one of the purest forms of cellulose in nature.
Why is all this important? Acid not only affects the sheet of paper in which it is produced. Acid migrates. It migrates into anything it contacts. The photographs which you keep in treasured albums are only as safe as the quality of the paper they are mounted against. Remember that great sale on Family Albums at the local discount store? The people who manufactured, sold and bought those albums probably knew less about paper permanence than you now know. You may have been one of those buyers, and you may want to revisit your purchase.
Choosing the "best" paper is like choosing the best diet. We are continually learning what foods are "good" or "bad". Depending what medical condition we are considering, or what journal we are reading, we may or may not salt our food. In the end we must eat, and we must choose a paper.
It is not appropriate to suggest that only the most permanent papers available should be used in all circumstances. It is, however, helpful to understand the characteristics and relative permanence of what is available. Art supply stores, flaming shops and photographic stores are a good source for help and materials. If the sales person who helps you knows less than you - buyer beware.
It is easy to be overwhelmed by the project of cataloguing our photographs. Ninety-five percent of my collection I would prefer to be used, rather than ignored. These items are not to be fretted over. But there are a few choice pieces that deserve special care and attention.
For these items, the plastics and papers they contact are important. I don't use unknown chemicals, glues or tapes to mount them upon paper. I never use rubber cement (it contains sulphur). Mylar photo corners make good mounts and work with all circumstances.
I don't store them in the attic or basement where humidity and temperature would destroy them. Putting them in a cardboard box for storage is one of the first things I had to change (remember the migrating acids). And I don't let people who look at these pictures point out Uncle Lou by putting their clean but acidic finger on his face!
Caring for photographs need not he a chore. Just remember they are chemically sensitive creatures, and everything else falls into place.
Wayne Hunt may be reached at (613) 526-9000
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