Ron - the Cibachrome name was in use well into the second generation of the medium. Ilfochrome didn't indicate anything other than a change
in ownership. All the actual product development occurred under Ciba-Geigy. That final owner was Oji paper of Japan, who grandfathered in the
use of the Ilfochrome label after Ilford England divested itself of involvement in the Swiss color mfg aspect. The RC "Pearl" version of Ciba/Ilfo dropped
off the map first.
Roger, back in my day there was no such thing as a color enlarger or even an enlarger with filter drawers. :D
Drew, There were several iterations of Ilfochrome paper and chemistry as they moved from one bleach to another. They went from H2SO4 to Sulfamic acid and changed the type of catalyst. We followed this closely at EK. You might not see the changes, but they were there even if minor. Even the dyes were changed slightly.
I spent about a year printing b&w before I felt confident enough to try Ilfochrome. Note that you would process Ilfochrome in closed rotary tanks, not in open trays, so the actual process it actually quite different from b&w processing. You should definitely get acquainted with your enlarger before you waste precious Ilfochrome material.
Originally Posted by AGagnon
As preparation steps you can practice in complete darkness all the handling steps from cutting the paper to size, putting it under the enlarger until you have it in the tank after exposure.
Ron - the commercial chemistry was sulfuric from the start. The powder sulfamic version was also from the start, but in low-volume retail
do-it-yourself kits. There were minor tweaks and temporary options to both. They offered a higher speed version of pro for certain machines.
I still have quite a bit of the pro chem on hand, more than I need for my remaining stock of frozen paper. Had a friend in here yesterday who
used to run a process line that required a 200 gal tank of the sulfuric bleach on hand. He gave up on Ciba after to had to have a lung removed.
I don't do commercial lab work, so even for big prints used just small volumes one-shot, ran the drums outdoors, etc. It was less noxious in this
mode than RA4 in my opinion. The amateur sulfamic version was slightly less nasty, but icould still mess up someone careless, just like
Oh yeah... the dyes did change quite a bit between the original Cibachrome and the "self-masking" second version. After that, the main difference was just a lower-contrast tweak on the same thing. Oddly, I think the original dyes were the more permanent of the two. But you
had those artsy types early on doing going goofy things with it, like developing in Selectol to get ghoulish greens, or exploiting the bright reds.
Typical adolescent use of a relatively new medium, just like with inkjet today. I can only think of two print I ever made which had a dominant
red. Ciba had a pretty remarkable gamut if you bludgeoned it to death with enough masking and avoided certain hue categories. It was a lot
cleaner than the chromogenic prints of the era... but they have since evolve along with color neg film to the point that even if Ciba could be
affordably reintroduced, I wouldn't switch back, that is, except for that stockpile of chromes I've got. All my new work is being done neg.
Drew, I knew the designer of Cibachrome and have coated my own versions of it for tests. We were working on a heat processed dye bleach print material at the time. The primary researcher gave a very nice talk at RIT during a convention here and I have copies of that work.
Kodak was working on a version as well, to be called Azochrome. It was coated on a support similar to that of modern Ilfochrome. I have a roll of the support here for my experiments in dye bleach if I ever get around to it. I have already posted single color Magenta here on APUG.
That's sure interesting, Ron. I do recall hearing the term Azochrome being floated around a long time back... but your inside history with it
is what is so intriguing. I wonder why Kodak backed off? Did Ciba jump the gun first, or was is just another one of those dead-end
R&D branches which Kodak never fully committed to?
I don't think it will even keep that long in the freezer, so I would not waste time with any that old. I had some in the freezer for less than 10 years and the color shift was uncorrectable. But if some is only a year or so old it may be worth a few test prints. Until then, keep it sealed from moisture and chilled.
Originally Posted by AGagnon
Drew, the introduction date for Azochrome was set at Dec 8th 1941, but a certain event intervened, and it was impossible to get some materials from the suppliers as they were used for other purposes.
I have spent some time looking for the name of the Ciba researcher and some of the data, but have been unable to locate it. It is in a file labeled "Dye Bleach" which is oddly appropriate, but at present, is invisible to my tired old eyes. ;)