Analog separation negatives from color positive film

[pkr1979]

Thanks again! And, densitometer chat moved to appropriate section

 

[DREW WILEY]

Few usable pigments are transparent. It is hypothetically possible to grind pigments so small that they seem transparent, but nobody has come up with anything close to a real process set of those. It's not something you can do with a mortar and pestle. Giant industrial firms worth billions have been looking into this for a long time, but certainly not with carbon printing in mind! The real money is in automotive and ship coatings. And a true process set of nano pigments would turn current inkjet printing into a dead dinosaur boneyard as fast the giant asteroid which hit millions of years ago. I was in steady conversations with such R&D of them for over twenty years. But it's still not realized.

True black pigment is surprising difficult to achieve. Just tone any alleged black can of paint with a little white and you'll discover it comes out either greenish or purplish.

There is really a bifurcation in potential output. Some people are aiming for a "different" look, and are not particularly concerned whether it faithfully represents the original color chrome or not. Some of the most beautiful pigment prints I've ever seen were made by Atelier Fresson, and none of the colors were realistic. On the other hand, a few people have been successful at making very realistic looking carbon and carbro prints; but it was an especially long journey. None of the modern commercial ventures I can think of lasted long. Dye transfer doomed carbro; dye transfer largely gave way to Cibachrome; and then inkjet printing doomed all of that commercially, but not necessarily as an advancement in visual quality or permanence, just convenience. But thank goodness there will always be people rebelling against the invasion of the machines, computers, and robots, who want to have as much tactile hands-on control as possible.

And to briefly respond to Koraks - aside from my own lengthy experiments, I've been in touch with quite a few accomplished alt color printers requiring highly predictable separation negs, and not one of them used stained negs. You can't even find something like that in old literature. It's not like monochrome UV printing. Every extra variable needing to be tamed can almost exponentially increase frustration. It's far easier in this case to selectively control highlight repro via supplementary masking if necessary. But again, all this depends on what you're after - just some unusual or special or fun look, or a high degree of process control.

 

[koraks]

And to briefly respond to Koraks - aside from my own lengthy experiments, I've been in touch with quite a few accomplished alt color printers requiring highly predictable separation negs, and not one of them used stained negs.

I agree; that's pretty much what I said earlier as well. I never recommended using pyro for color separations because IMO it would be pretty difficult to pummel pyro into sufficient linearity for this purpose. My remarks concerned yours about base density and lack of image-dependent stain; my experiences seem to not match yours in this respect. Mind you, I have only used 510 pyro and pyrocat; can't vouch for Rollo, 123 Pyro, PMK etc.

 

[pkr1979]

Thanks again guys. What would be a reasonable exposure time for the separation negative? To start out with.

 

[DREW WILEY]

Hi again, Koraks. Yeah, there are a lot of pyro formulations, and I experimented with a variety of them, both pyro-C and pyro-G based, even formulated a couple new tweaks of my own. But for general photographic usage, I standardize on PMK. Special lab project developers are in a whole other category. And when it comes to taming color separation protocol, one not only needs to have at least a black and white transmission densitometer, but should expect to be married to one for quite awhile. In terms of how to make and use an elementary DIY "visual densitometer", one can search my past threads for my posting.

pkr - what constitutes a reasonable time must first of all be entirely predictable with respect to your exposing light source. Most enlarger heads, unless equipped with synchronized shutters, has a brief warmup phase, and final die-down phase. So you need to have at least 10 or 20 seconds of exposure to assure repeatable consistency. But anything too long, and you run into reciprocity failure issues hard to predict, because they potentially affect the three different light colors of exposure differentially. I personally standardize on 10 seconds because the math is so simple with respect to that. And the contact printing frame holding the film must be precisely centered on the baseboard directly below the lens itself each time. Use a long enough enlarging lens, and proficient diffuser, so that illumination over the film area itself is fully consistent, with no falloff.

But I have very sophisticated controls on my colorhead, plus a very precise rare easel densitometer far more sensitive than any lux meter. You can adjust for different negs via a bit of aperture control, but you don't want drastically different apertures due to potential halo or mis-register between the respective negs. I'm speaking in an advanced sense; but that's what you need to aim for up front unless you want problems later. It takes a lot of repetitive practice to peg everything down, just like first learning the chords to a piano. One step at a time; you'll get there.

Remember, for sake of the long run, you'll need to come up with several different matched sets of experimental step tablet negs having distinctly different contrast gamma levels. That's because you don't really know how much contrast you'll need until you start experimenting with your own coatings and chosen pigments, hand-in-hand. So it's helpful, even vital, to have "families" of matched contrast curves to choose from, and not just one successful example.

 

[sasah zib]

 

[DREW WILEY]

Cute flick. Does anyone remember that movie where Cathy Bates set up a stand at the fork in a dirt road, selling caged squirrels? "Wanna buy a squirrel?" If they said no, she directed them onto the fork which went right over a dirt cliff, with a big pile of smashed cars down in the ditch below. Crawling out of a smashed car in a ditch, over and over again, would be good practice before heading into color separation work. You need to learn patience, and that successfully getting to your destination is going to involve some pain first.

 

[pkr1979]

Thanks again - much appreciated