Artichoke wrote:
I have a box with a couple of hundred 4 x 5 black & white negatives dating from around 1950 that my dad took (irreplaceable family photos). It smells like vinegar. Is it safe? I assume it's not going to spontaneously combust like old nitrate motion picture stock used to, but is there a danger of some kind of deterioration happening?
Your question is about conservation of photographs, so you should be asking a
photograph conservator. Most large museums can refer you to one.
Sounds like those negatives are suffering from "vinegar syndrome". This happens when
cellulose triacetate stock breaks down though a process of deacetylation. It is safe to you,
but the images are in danger of being lost forever.
https://en.wikipedia.org/wiki/Film_stockhttps://www.filmpreservation.org/preservation-basics/vinegar-syndromeImmediate action may be necessary to save them. Generally, cold storage is the
only solution once vinegar syndrome has set in. Howeer, cold storage must be done properly.
https://www.archives.gov/preservation/storage/negatives-transparencies.htmlhttps://albumenworks.wordpress.com/2013/07/17/negative-deterioration-part-two-cellulose-acetate-negative-conservation/As a "fist aid" measure, you should remove the negatives from any contact with wood pulp
paper (nearly all paper made in the last 120 years). Attempts to buffer such paper with alkalai
(often sold as "non acid paper" or "archival") are temporary at best. No wood pulp paper is
truly permanent. Eventually, it will attack itslf and negatives it is in contact with. And the
alkalai added to buffer the paper can leech out and cause problems.
If any negative is in a paper envelope, you should move it to a plastic sleeve.
Negative holder sheets are available for most negative sizes. If there is a caption or date
written on the paper, then it can be folded to fit in one of the sleeves next to the photo it
refers to. Be careful not to toch the surface of the negatives---conservators usually
wear white cotton gloves (available as disposable gloves for artists).
All film should be stored in an environment that is:
* as cold as possible
* neither too damp nor too dry
https://www.filmpreservation.org/preservation-basics/film-decay-and-how-to-slow-itThese requirements are somewhat difficult to fulfill simultaneously. It is better to err
on the side of too dry than on the side of too damp.
I store old negatives in my freezer in a sealed plastic container together with:
* an acativated carbon packet to absorb any acetic acid gas
* a silica gel dessicant pack
These are available from many sellers, you coudl try Amazon.com.
These will need to be changed periodically.
I like the clear packets containing blue silica gel that turns red when it needs
to be "recharged" by baking. (follow the manufactuer's instructions).
I'm sorry the news isn't better. But just getting them out of paper envelopes
and moving them to a cooler place in the house is a step in the right direction.