The ghostly effects of platinum images

I recently found this platinum print, nearly panoramic by virtue of being two separate prints attached at the center. It's a platinum print of the sepia variety and what made it interesting to me was the dramatic image transfer effects that occurred as a result of being stored folded. Each half of the image has "transferred" itself on to the other half. For example, the two women standing in the flower garden on the right side also appear as ghosts in the road on the left side. Both of the buildings have also transferred their mirror images to the opposing side. The best explanation for this image transfer effect has been posited by Mike Ware. His theory goes something like this: the platinum image metal plays a key role in the conversion of sulfur dioxide (an air pollutant) into sulfuric acid, which causes the brown discoloration of the paper. We often see this effect on paper folders and protective tissues in contact with platinum prints and also on paper materials in contact with matte collodion prints (which are toned with platinum).

Kodak Notch Codes in the 1970s

Although I'm planning a much larger article on notch codes and the decoding of other information on (mostly Kodak) films and prints, here are a few notch codes for (mostly) 1970s color material that might be useful to some. All images are from different editions of the Kodak Color Dataguide:

Kodak Color Dataguide

Kodak Color Dataguide 1966

Kodak Color Dataguide 1971

Kodak Color Dataguide 1974

Kodak Color Dataguide 1975

Kodak Color Dataguide 1976

Kodak Color Dataguide 1977 supplement

Kodak Color Dataguide 1978

Kodak Super-XX Film Pack

Following a discussion about pack film on the Photohistory listserv I acquired an unopened Kodak Film Pack. The "Develop By" date on the package is March 1955. I will annotate and add further information, including pictures of developed film negatives at some point. But here are the pictures for a start:

A 4x5 pack film negative showing the adhesive attachment stain along the right edge, and the negative number exposed onto the negative in the lower left corner. The image is blurred and possibly out of focus. Some of the original adhesive is still present along the left edge, but even where the adhesive is absent a brown image or stain remains in the film. This could have been caused by a chemical reaction between the adhesive and the silver image or by the pressure involved in applying the adhesive tape during manufacture (pressure exposes silver halide emulsions).

Film Pack Diagram from C.B. Neblette, Photography: Its Principles and Practice, 3rd Edition (1938)

Boy Scout Jamboree: Dufaytissue from Dufaycolor

I recently acquired a few Dufaycolor transparencies and with them came a single print of a type I had never seen before. After a little research, the print appears to be a Dufaytissue (Dufay Tissue?), a modified version of the tricolor carbon process using carbon tissues on acetate supports for the individual color layers which are then assembled on a paper support. Although my example may not be typical, the Dufaytissue lacks detail in the highlights and shadows as well as sharpness compared to the original Dufaycolor transparency. This Dufaytissue image degradation is likely common given the difficulties inherent in making a continuous tone print from an additive screen plate with its color mosaic. Both images measure 6x9 cm.

Dufaycolor

Dufaytissue

Candlestick Antiques / Flea Market

The Candlestick Park Antiques & Collectibles Faire opened today in the parking lot of San Francisco's Candlestick Park, home of the San Francisco 49ers. July 18, 2010 was the opening day for this new San Francisco flea market, and a welcome addition to the Bay Area's flea market scene. The SF Chronicle had a nice article on them yesterday, and if all goes well they'll be happening the third Sunday of every month. I went to this inaugural day to see what photographic treasures might be found, and I was not disappointed.

I found 3 photolithographs (also called Photochroms) made by the Detroit Publishing Co. of Detroit's Belle Isle park. The Library of Congress has some info on them, and the Wikipedia entry on Photochrom is another good resource. Photolithographs are a rather unusual process, and I have not found many of them in my years of antiquing. Here's two of the prints that I found:

And here's what they look like under magnification!

I also found a nice overpainted salt print

And a nice example of image transfer on a matte collodion print, the result of the catalytic action of the platinum in the image which converts sulfur dioxide into sulfuric acid and turns the paper brown where it is in contact with the image (at least that's my current understanding!):

No carbon, but still potatoes...

...well, some kind of starch anyways. Thanks to my collaborator-in-all-things-color Zach Long at the Image Permanence Institute, I can now show you photomicrographs of the Alticolor film with an expiration date of July 1956 that I recently acquired. Given the date, this is from one of the last batches of the last form of the screen process originally introduced as the Autochrome in 1907. As I mentioned before, I have heard rumors that, at some point, carbon black was no longer used in the manufacture of the Lumiere additive screen processes, and that yeast grains replaced potato starch grains. Well, this Alticolor film does NOT use carbon black to fill the interstices between the grains (see upper image), but it DOES still use starch grains (as evidenced by the Maltese cross in each grain under cross polars-- see lower image). While it would be nice to have a more complete picture of how the various "Autochrome" products changed over time, this will have to do for today...

Dufaycolor

The last significant additive screen process to be introduced was a modification of the original Dufay dioptichrome process from before WWI. First released as a motion picture film in 1932, it was introduced for still photography in 1935 in roll, sheet, and film pack forms. A very fine screen structure, increased sensitivity, and simple reversal processing kept it in use into the 1950s for still photography.

Its use in motion pictures was short lived, though long enough to produce a number of feature-length films in the 1930s. Although not present on this sample from the Eastman House Film Technology Collection, a variable density soundtrack could be printed successfully into the image area.