Pinatype dye structures
Capstaff's patents for his two-color process call for an "acid dye (preferably the salt of a sulfonic acid)", US 1196080; US 1315464. Only the dyes which you cited fit this description: lanafuchsin & quinoline yellow. The dyes carmine and indulin blue clearly are not sulfonic.
Pinatype dyes were used to dye the planographic matrixes over and over again. The matrixes could produce as many as twenty prints. The presence of aniline groups in indulin blue and the lack of SO3 groups in it and carmine indicate that these dyes diffuse more readily out of gelatin than dyes with more SO3 groups, groups which would have the effect of binding more substantially to the gelatin.
The Capstaff process was for "one off" assemblies of transparencies. While a dye transfer to blank paper over a period of ten to fifteen minutes would preserve the highlights, Capstaff required that the gelatin be thoroughly dried before dying, (Wall recommends drying for as long as three hours). A print surface so dried would be harder and much more likely not to absorb dye in the tanned highlights; even dyes with more affinity for gelatin such as salts of a sulfonic acid. It is possible that a wide variety of azo dyes which are salts of sulfonic acids would work in the Capstaff process. So a set of dyes suitable for DT and DB might be found.
Gaspar had a special colour seperating cine-camera made. However it took three colour-separations in high-speed succession, what nevertheless hampered filming fast moving objects. Added by the low speed of that colour film system.
Originally Posted by falotico
During Gaspar's European period hat silver-dye-bleach film was made by Gevaert.
Last edited by AgX; 01-30-2013 at 06:27 AM. Click to view previous post history.
I am aware of those processes and patents. I was pointing out that Indulin Blue is not a sulfonic acid dye and therefore was probably not one that Captstaff really used. I also point out that a DB and a DT system could be built using the same dyes if they were all from the Azo dye family.
A multi-use set of Azo dyes both for DB and DT would be very convenient. It might also be possible to combine the two processes: develop with a tanning developer, let the dye transfer into the whole matrix approximating the correct tones, and then bleach out the highlights.
From the language of the patents Capstaff seems to indicate that he uses only one dye per color. It also seems that his images from Capstaff Kodachrome were all assemblies requiring silver halide emulsions on transparent bases. I recall seeing a two-color portrait of George Eastman(?) from the 1920's which was published in the Time/Life book on photography called "Color", (1978). That gives some idea of the color values; the warm tones were somewhat orange. Looking through samples of dyes available at that time with the correct chemistry (acid dyes which form salts of sulfonic acids) it might be possible to rediscover the dyes that Capstaff used. The Colour Index gives structure, hue, lightfastness and date of discovery.
Capstaff invented two versions of DT: the first tanned the highlights with a bi-chromate bleach in the standard manner; the second tanned all the gelatin with ferric chloride and tartaric acid and then de-tanned the lowlights with a UV light image. I assume each version used different dyes. IDK which version the portrait in Time/Life "Color" used. I would love to see a Capstaff DT in the flesh.
I have seen examples of European Gasparcolor on Youtube. Gaspar moved here to California before the war and lived in Beverly Hills. He donated all his papers to UCLA and these are held by Special Collections. I wonder if he had Gevaert coat his films after the war. IDK who did that work for him.
All of the Capstaff work may now be at the George Eastman House.
As for a single dye set for both DB and DT, that is my goal as then you can match the prints using different methods. And, DB and DT materials are rather easy to coat yourself. None are in production at this time, but Jim Browning has posted a formula for the Matrix Film, and I have suggested elsewhere on APUG that a hardened version in a multilayer film or paper might be used for DB.
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Jim Browning posts the three dyes he uses for DT along with his formula for matrix film at http://www.dyetransfer.org/. These dyes are:
Acid Blue 45- C.I. 63010
Acid Red 80- C.I. 69215
Acid Yellow 11- C.I. 18820
Only Acid Yellow 11 appears to be an azo dye, but it might be suitable for DB.
All the structures I can find for Chicago Blue are diazo (cf. Chicago Sky Blue 6B- C.I. 24410); the dye for the DB emulsion in "Photographic Emulsion Making" Solantine Pink is also diazo, C.I. 25380. Do the Chicago Blue or the Solantine Pink in this DB method transfer?
If I can get out to Rochester, NY I would like to see what I can at the George Eastman House.
Jim has used Solantine Pink and Solantine Yellow, as have I, for DB and for DT. The pink is a bit short but is rather like the old magenta in Ektacolor 70 paper.
So, the pink and the yellow both transfer and work with DB. What we lack is good information on a cyan, and we may need a better magenta.