View Full Version : Tr-Color Neg creation

David Nash
22-Feb-2005, 13:30

A few years ago I tried tri-colour gum printing, without much success! I'm now going to go back to basics, and thought I'd initially try scanning the negs into Photoshop etc before learning the intricacies of gum printing!

I have a Lee tri-colour filter set. I first of all need to work out the filter factor for each of the three colours. I'll then meter for the scene, then photograph the scene with each filter in turn, adding the appropriate filter factor for each colour.

If if this is correct so far, my main question concerns developing the negs. Can I process the three negs at the same time (ie with the same development time), or do each of them require different contrast?

I'll try this first, then I'll probably post a question about layering and colour subtracting (or whatever the term is) in Photoshop later!



22-Feb-2005, 13:36
I can't help you with the gum prints, but I stopped doing Dye Transfer 30 years ago and think that I still have a hair shirt in my closet which I could send you.

David Nash
22-Feb-2005, 14:20
Thanks, Bill. You're a gentleman! Please send it on the next clipper bound for Great Britain...

I couldn't sleep last night, and ended up reading an old photography manual (dated 1932!) where colour photography for everyone was just a pipe dream. However, it made me want to investigate for myself. There's just something about the idea of making a colour print from B&W negs that sounds almost unbelievable (I'm not a physicist!), and I'm keen to see it happen under my nose!


Graeme Hird
22-Feb-2005, 14:29
I'm interested in this process too, since I believe that I may be forced into doing my colour photography this way eventually (when the film makers stop making the film I like). Any answers you get here David will be stored away for later reference.

However, I don't think I'll need to get serious about the process for a few years yet.

My gut instinct says you should give all three films equal development and exposure (ie - don't change the contrast).


Larry Gebhardt
22-Feb-2005, 14:34
My gut feeling is you will need to adjust the exposure because tmax isn't linear over all the colors. I would start with the same development and adjust contrast in photoshop if you need to. Use this as a guide for the next set's development.

Let us know how it turns out.

CP Goerz
22-Feb-2005, 15:15
The blue neg will need twice the development of the red and the green will need one third more. This was from a guy I chatted with who at the peak of his creative output with everything going perfectly could make two carbro prints a day.

CP Goerz

Jim Galli
22-Feb-2005, 15:28
Not a few times on Ebay and once in person, I've seen the beam splitting cameras that seperated the 3 colors and sent them to 3 planes and make all 3 negs at the same time. They aren't very expensive as there's only one guy left on earth that wants one. Saw one in Reno that was 5X7. Wouldn't that be the best place to start? When you get the hair shirt, make sure you wear it "hair in". This is punishment right?

22-Feb-2005, 16:12

If you see another of these old tri-color cameras available in good condition at a decent price yell at me. I am another of those guys on earth who would like to have one of these, preferably a 5X7. I would really love to make some tri-color carbro prints using separations made with the equipment they used in the old days.

Jim Rice
22-Feb-2005, 17:34
So am I insane for wanting to make dye transfer prints?

Jim Galli
22-Feb-2005, 18:07
Jim, Only slightly more so than any other LF wacko. Contact me off line if you want a bunch of Agfa stuff that came with a large darkroom buyout. I don't know what the stuff is but it's something to do with dye transfer I'm sure. Would happily trade for a finished dye transfer print someday. Jim

Paul Fitzgerald
22-Feb-2005, 19:03
Hi there,

Never touched this and never will, I just read the Kodak Graphic Arts data books.

the easy choice:

1) make your tri-color seperation negs, adjust filter factors and dev.

2) make contact positives from R, B, G., adjust exposure and dev. times.

3) mix and match the positives with different negs to make color correction masks.

4) mix correction mask with neg. to make the black mask.

5) mix neg. & correction mask, print 4 times and of course everything will be in perfect register

6) if the gods are laughing, you might get something.

They have neat little targets so you can get 3 points on the H&D curve to match up. Yes you do have to check the film for exposure thru a step wedge with the filters you use, the light temp. and the dyes you will use. If anyone wants, I have twins of this and will send one along.

"So am I insane for wanting to make dye transfer prints?" Yeap!


22-Feb-2005, 19:15
There were two brands of tri-color cameras: National and Curtis. I don't believe that either of them would focus close enough to make copy negatives from trannies.

Donald Qualls
23-Feb-2005, 05:39
The other thing to keep in mind with tri-color gum printing -- you can adjust both density and contrast at the printing stage, as well as in the negative. If (for instance, and likely) your yellow printed layer isn't dense enough, print that layer again (right over the existing layers) to add density, and make notes so you can increase either pigment loading or contrast (by increasing the sensitizer loading) in the next print from that negative set.

BTW, if you're going to make digital negatives anyway, why not just shoot in color and do the separation in Photoshop? Then you can adjust the curves, contrast, etc., and make a new set of negatives in twenty minutes (from the same original image) if you don't like the way they print. Additional advantage is that your registration pin punches don't have to be in imaged areas of the negative and/or you don't have to compose to allow for the crop required by those punches.

Also, the art world, at least, doesn't seem to demand perfect registration in tri-color prints -- they like to be able to see it's handmade, apparently, so you may be able to avoid using a punch-and-pin registration system that will set you back a month's rent. And relative to carbro and two prints a day -- gum is much, much simpler to get acceptable results than carbro; you can reasonably expect to finish a gum print in 4-6 sessions of twenty minutes to a half hour each, not counting drying time or time under the UV light exposing (which might run to an hour or two per exposure, but you can do other things while the timer runs down); if you're making a lot of them (and have enough copies of things like contact printing frames and negatives), you might reasonably expect to turn out 5-6 prints a day when things are going reasonably well. I've also seen (images of) very nice prints using cyanotype in place of a cyan layer in tri-color gum -- that is, a cyanotype from the red negative, and then gum layers printed over that to make up the tri-color print. Cyanotype is significanlty quicker, easier, and cheaper than gum. Now if there were only corresponding processes that would produce magenta and yellow images...

David F. Stein
23-Feb-2005, 08:12
Go to the LIBRARY OF CONGRESS web site. There is a gallery of images taken by a Russian photographer in late Tzarist times just as you would like to do. There is a complete description of how the staff scanned, corrected and re-assembled the separation negatives to create new "originals." Some of the images are excellent and like so many other LofC stuff you can download files and print the images yourself. There is also a treasure trove there from WPA days, Ansel Adams, etc. GOOD LUCK and in the vein of Back to the Future, I think what you are interested in will be quite popular. Just don't let Sally Mann overhear you!

Al Seyle
23-Feb-2005, 14:02
Hmm...reminds me of Mr. Streeter's Color I class at Brooks Institute, circa 1968. As we all said then--"I'll never make another dye transfer print as long as I live, but it's a great way to learn color theory."

Good luck.

23-Feb-2005, 14:35

Jim Rice
23-Feb-2005, 16:28
It sounds just like my cup of tea, actually. I seem to specialize in the gathering of archane (alas mostly obsolete) skills. Does J&C still have matrix film?

Jim Rice
23-Feb-2005, 16:33
And Paul. If that twin needs a daddy contact me offline.

David F. Stein
23-Feb-2005, 19:04

David Nash
24-Feb-2005, 15:20
Thanks, everyone. I've got a bit more info now. I'll probably end up posting a few more questions - I've got a new one already!