Gasparcolor was 3 color and used dye bleach.
Gasparcolor was 3 color and used dye bleach.
Steve, thanks for posting that, it looks really great! PE's right though; it's 3-color dye-bleach system, a precursor to Cibachrome, developed by Hungarian Bela Gaspar. A very interesting process, but only useful for printing color from separations, not capturing color directly from the scene (IIRC). It was widely used for animation also.
Coming in here a bit late, I'm pretty much thinking out loud, and it's probably a stupid question, but would it be possible to use C-41 or E-6 type couplers, in solution with one of the CD's, as a second developer on standard, reverse exposed B/W film? Or do those families of couplers have to be adsorbed to the silver halide crystals to work? (So what I'm envisioning is sort of a split K-xx process, where the couplers and developer are in the same solution, using two -- or three -- separately exposed standard b/w films, which would then be sandwiched.)
I think PE has said you could do this with the Kodachrome couplers, but since those aren't readily available, that's not a viable solution.
Yes, I've done this for well over over 30 years for colouring B&W prints, I use raw couplers but Tetenal made a dye coupler kit, not sure if it's still available. Jave alsom used colour couplers with B&W films.
yes--I'm reading up and I think I can start off using something like the formulary toners for paper--there's an iron toner that'll give me green and a copper toner that'll give me red...for 2 color process, all I have to do is then just find the right filtration and relative exposure and hopefully I get something looking like that early kodachrome---
for more flexibility I guess the mordant and dye is the way to go, but then it's time to start hunting for dyes and experimenting...
I'm thinking of a 2 color--direct reversal (2 positives--one a reversed image)---the silver is toned using the copper for one and iron for the other or suitable mordant---apparently the mordant method would simplify and speed things up--I can apply the morant after the dichromate bleach step and skip the whole regular reversal development process....just develop-bleach-mordant-dye-develop-DONE, right?
Couplers are not mordants.
Mordants are chemicals that hold soluble dyes in place in some material such as cloth or film. Couplers are materials that form dyes through a two step or three step process involving a reducing agent and an oxidizing agent. In film, this is the Silver Halide and the developing agent.
It'll be interesting to see if the toners can do the trick; maybe so! There were a couple dye-toning tri-color processes too, so it just goes to show you that toners can create a wide range of usable colors.
I've not really looked at the mordant processes seriously yet (in terms of the procedure) so I can't be certain when in a reversal process you'd wanna stick it. I think though, that you'd need to develop up the positive silver before you could turn it into the potassium iodide mordant, viz. the Ives process.
Finding dyes for this might not be hard. There are a thousand basic dyes on eBay that are used in biological staining and other things. Malachite green is one from the top of my noggin.
Alternatively, if you look at Capstaff's patents on this process, his method for sticking the dye in the gelatin is by a dichromate bleach not unlike one found in reversal processing or carbro. Heck, the first patent (IIRC) goes from a negative to a dyed positive via this bleach in one step. He later patented a method to do this from a positive to a positive (better for printing to movies).
Although chrome salts can be mordants, in this instance it's not strictly lending any mordant action, but rather it's the hardening differential set-up in gelatin that "involves" the dye. This requires acid dyes, loosely speaking, that might easily be found in the textile industry.
Sorry if I'm repeating myself a bit; some tricky concepts here, and I don't think it hurts to reiterate and say things differently. It certainly helps me make sense of it all too...
In the end, I hope you give it a go with any method you like!
This is a really amusing little multimedia thing from PBS. It actually takes you through making a Capstaff Kodachrome... well kind of.
Anyways, pretty cool, check it out.
awwww...I thought they'd show the 2 color camera and everything...not even close--just a tutorial....
I've seen something similar to this before--very similar but with the full 3 colors--same type of demo-"you build it".