Since beginning the project two months ago, we’ve already run across some interesting formats from the 1950s, formats that were once common in office settings and now seem quaint. We’ll start with a random (way overstuffed) folder from HIAS’s executive office.
You can see how the pressure from the documents packed too tight has caused many of the documents to curl around the others. These documents are usually on very cheap paper, so overstuffed folders can lead to different preservation issues depending on the format of the document in question.
Onionskin is a kind of paper we find a lot in records from the 1950s. It is very thin, lightweight, and translucent, making it a good stock for carbon copies, permanent filing, and airmail–helping businesses save money on storage space, postage, and copy typists. You can see in the photo below how thin this paper really is.
The issue we find is that it’s very easy for onionskin paper to get mashed up by the thicker paper around it. Here’s an example of some onionskin that has been crushed up against a box for decades. Notice how the acids in the box’s cardboard have browned the ends of the sheet.
Luckily, onionskin is pretty durable. It has a high content of cotton fibers, making it strong and flexible as well as containing little-to-no acidic lignin, which causes most paper from this era to yellow and crumble. At the same time, this durable paper holds a crease very well. If a sheet of onionskin falls down in the back of a slumping folder, you get something like this:
However durable, it’s still an incredibly thin stock, leading to some easy tears. Back before photocopiers and desktop printers, a lot of hard labor was saved with the help of scotch tape. Unfortunately, the glue in scotch tape is not particularly stable and the adhesive is often very acidic, eating its way from the back . . .
. . . to the front.
After sixty years, though, most of the adhesive has dried and the tape itself is so desiccated that it peels right off without a problem, though that’s not always the case, as seen in the photo below.
Old, acidic, wood-pulp-based paper slowly disintegrates over the decades until it is brown and very brittle.
Here you can see how easily brittle paper cracks . . .
. . . and flakes off.
There are also reproduction formats particular to this time. Thermofax was a photocopy technology introduced by 3M in 1950. The process used infrared light, which was absorbed by the black ink of the original document, heating it up, and that heat would then transfer to the special heat-sensitive paper, resulting in something like the document you see below.
The problem with Thermofax is its tendency to darken over time, due to the heat-sensitive leuco dye embedded in the paper. Over time, the dye continues to develop and is often corrosive to surrounding documents as well as the copy itself, which becomes brittle over time. You can see here how much this document has lost contrast (though, it’s difficult to say whether this is solely the work of the passage of time or of the very inexact and temperamental Thermofax process).
And the final uniquely mid-century format we’ve run into (so far!) is Agfa Copyrapid. Introduced in 1949, Copyrapid is based on a process called diffusion transfer reversal, which is very similar to silver-halide-based black-and-white photography (in fact, the diffusion transfer reversal process was key to inventing instant cameras such as the Kodak Land Camera).
Instead of projecting light through a transparent negative onto light-sensitive paper to create a positive image (much like traditional black-and-white photography), Copyrapid uses a special negative transparency that is exposed to light reflected off the original document. The image on the negative is then physically transferred to a special sheet of copy paper by pressing them together. The transferred image shows up as a positive image.
Don’t ask us how it works. For all we know, it’s just mid-century magic. Hopefully, we’ll keep running into interesting obsolete formats and posting them here, and rest assured we will continue to do our best to flatten curled and crinkled documents, capture fading text, and give the documents a better chance at surviving intact for the foreseeable future.