Monday, August 3, 2009

Ongoing efforts to clean and flatten flood-affected archives manuscripts from the African American Museum of Iowa have turned up yet another form of adherograph deterioration. (See June 30, 2009 entry)

As seen in the example to the left, the powder medium that holds the adherograph text image has irreversibly adhered to the back of a preceding document page.  Unable to separate the two, I decided to scan both pieces of the damaged document and then attempt to reunite them in Photoshop.

The first step was to flip the fragment horizontally.  Though only the back of the reversed fragment text was visible through the adherograph medium, flipping it over digitally created a faint, though workable positive. 

Note the altered color of the reunited fragment.  Through a haphazard process of tweaking color levels and saturations I was able to pull the text out, making it as legible as possible.  After doing so, reducing the image from color to black and white serves to isolate the information from the discolored document carrier.

 This detail, captured after converting document to black and white, shows that while the texture of the adherograph medium remains cumbersome, the information is again legible. 

This second example details another completed document as well as its original post-flood condition.  While this process is probably too time consuming in many situations, experimenting with the procedure was a valuable experience.  Not only is there now a workflow for this in the future, but it also raises some interesting questions about disaster recovery, institutional resources, and policies pertaining to discarding and reformatting.

Monday, July 13, 2009

Many of the files from the African American Museum contain various forms of correspondence. There are many postcards and letters with their original stamps. When these already fragile envelopes were faced with the flood, the stamps detached to end in a pile at the bottom of the file folder.

The second project I gave Kallie was to reunite the stamps with their respective letters and postcards. This was a fun project because it’s like putting together a puzzle and some of the stamps are pretty interesting. I had her reattach the stamps using wheat starch paste applied with a small brush. When the stamp was in position, a small square of blotter was placed over it and weighted to absorb any excess moisture and prevent warping.

Tuesday, June 30, 2009

While processing manuscript archive documents from the African American Museum of Iowa we fortuned upon an old, mysterious and extremely problematic form of document duplication.

What we believe we have, perhaps hundreds of, are adherography documents.  A definition, found in “Guide to the identification of prints and photographs : featuring a chronological history of reproduction technologies” – a supplement to the book “Encyclopedia of printing, photographic and photomechanical processes,” by Luis Nadeau, 2002 – is as follows:

ADHEROGRAPHY: A duplicating process developed by 3M. Images were formed by the adherence of powder to a tacky latent image created by the effect of infrared heat. This provided a master from which 200 to 250 copies could be made. The powder image of the resulting print was fused to the paper by heat. [A process used during the 1960’s.]

These adherographs, recognized as inherently volatile, did not respond well to the moisture, humidity, and high temperatures generated by last June’s floods.  The powder image described above, once fused to a slick-feeling, glossy-looking paper carrier, have lost their bind to their paper hosts.

Reformatting is simple where the powder images free themselves in large pieces.  Unfortunately, many of the documents have experienced a shattering of the powder image layer.  Attempts to stabilize these particular documents in sonically-welded Mylar encapsulations have both pros and cons.  On one hand, the Mylar, having a strong static charge, lock the powder image fragments into place… useful for reformatting.  On the other hand, this same static charge has the tendency to agitate the fragments into incomprehensible disorder.

With the jury still out on encapsulation, we simply reformat through the best possible means.  Where the documents are relatively stable, we quickly scan them face down on the Ricoh.  Where the documents are highly volatile, we image them under the Zeutschel top-down scanner.  No digital files are maintained.  Determining the best solution for the shattered documents requires further research.  Stay tuned.

Tuesday, June 16, 2009

One of our biggest workstreams at the moment is the rescue of the files from the African American Museum. We have over one hundred boxes of manuscripts which unlike the working files, which can just be photocopied, need to be saved. They are mainly records and correspondence, there are some photographs and newspaper clippings and other miscellany. These boxes were all submerged and the wet boxes smashed into odd shapes so sometimes it’s a trial just getting the folders out of the boxes! The fact that the museum used waterproof boxes saved them. While they were damaged, the boxes took the brunt of it. The files are warped and did get wet but most of the mud and dirt stopped at the boxes so there is minimal dry cleaning. There is some staining from the water but mostly on the edges of the paper and it is purely cosmetic.

Before any treatment we’ve been discarding and replacing the boxes and folders, carefully transferring all the accession information. They were all well labeled which makes it much easier to keep things in order.

I’ve been separating out the photographs as we haven’t yet determined a treatment plan. The bulk of the file material is paper which is warped and dirty. We dry clean the sheets and then flatten them. The flattening method I’ve been using is using a spray mister to moisten the pages and then sandwiching them between sheets of blotter in the press. The water relaxes the paper to help eliminate the creases. The blotter paper is a very absorbent material which takes up the water as the pages are pressed under weight. The sheets come out perfectly flat and dry. If a sheet has water soluble ink I mist the blotter very slightly instead of misting the page directly to avoid feathering. Since the files were submerged most of the ink that would be affected by the water has already so it’s easy to tell where to be careful.

While they aren’t pristine and do still have a slight eau d’flood aroma they are mostly back to normal and mostly in good working order.