Making separation negatives using RA-4 material?

T-grain · Dec 2, 2011

OK, maybe I am reinventing the wheel, maybe this issue has been previously discussed at length (IDK), so I apologize in advance if this is the case.
And maybe it would be better to post this contribution to Chris' dye transfer post.....
But anyway:

I was thinking how nice it would work if one would separately expose a slide with all 3 colors on 3 sheets of RA4 material (possibly transparent), like Kodak Endura transparency, or some Ilfocolor transparent material. (just to check, ordinary RA4 paper would be perfect).
Then, you develop those exposed sheets in some ordinary BW developer (with no chromogenic activity) to get the desired contrast. Then you fix in your ordinary BW fixer and you get a BW negative image derived from one color only. PLUS, you can work with a dim 590nm light, not in total darkness (as you should with a panchromatic material).
Then you would get 3 negatives ready to be printed onto your gum-bichromate, carbon, DCG or any other material requiring contact printing with a UV source.
That would be the "analog route" to big negatives, doable in an average darkroom, without some expensive hardware (you don't even need an inkjet). And probably, any RA4 material is reasonably priced (since it is a mass product)

what do you think, fellows?

Curt · Dec 2, 2011

I have no idea but keep investigating it.

Photo Engineer · Dec 2, 2011

Why not use LF sheet film then? That would work. The transparent Endura is really a bit translucent. It is intended for poster ads.

PE

DREW WILEY · Dec 2, 2011

I'd be concerned about the linearity, ability to boost and balance contrast to suitable DMax, and cost. But if you want to try it, what the heck?

wildbillbugman · Dec 2, 2011

I have used Kodak Duraclear RA-4 clear film for this very Thing, I have 3 huge 24x24 multi-layered separation prints made like this. Today, Duraclear is digitaly exposed using tri-color lasers, but still developed via RA-4. Cofusingley, Duraclear is transparent. Duratrans is translucent. It will still work using an enlarger.
Bill

wildbillbugman · Dec 2, 2011

T-Grain,
You just gave me an idea. Like 4 simultanius,and very different, projects are not enough for me. Today's digital negatives employ not only density, but color(hue) for optimum absorbtion/reflection for a given process. There are several methods published for generating curves for optimum digital negatives. It occured to me that the same thing could be done with an analog (RA-4) processed transparent color film. An expensive way for making negatives! But why not?
Bill

Photo Engineer · Dec 2, 2011

These curves with masking and C/M/Y/K images were used in the printing industry for years.

PE

wildbillbugman · Dec 2, 2011

Yes P.E.
I' m realy good at reinventing the wheel. But then, the wheel has been reinvented thousands of times. Try puting wooden wagon wheels on a BMW.
Bill

Photo Engineer · Dec 2, 2011

Bill;

I've done that myself at EK a few times!

PE

T-grain · Dec 3, 2011

thanks, guys! looks like something interesting is developing out of this post (pun intended)
PE, even if Endura is translucent-this is probably the back of the material, probably not an issue, or the same (not to the same extent) as when using paper negatives? isn't sheet film a bit more expensive than RA4 material? that's why I came to the idea of using it.....
Bill, thanks for the info, and I am glad that I am not the only "reinventor of the wheel"

T-grain · Dec 3, 2011

Drew, I have no idea so far what kind of curves one might expect from this, but I believe one can tune the whole system for his/her needs (BW developer, % of dichromate etc)
maybe tedious (painful), but doable

Photo Engineer · Dec 3, 2011

Ok, we were reminded above that there is a transparent version of Endura so that is not a problem.

As for using film, yes it is more expensive. But, I think that the curve shape difference is what you may want to consider. Films have a contrast of about 0.6 while viewable transparency film have contrasts of about 2.5, or a viewable contrast of about 1.7. That may enter into your consideration of what to use.

PE

CMB · Dec 3, 2011

Take a look at Webb's 1940 Patent#2196133 :

"This invention relates to improvements in photography, particularly color photography, and has for its principal object to provide a relatively simple process whereby superimposed silver images in multi-layer photographic material (film or plate) may be isolated in such a form that they can be employed as separation negatives. "

wildbillbugman · Dec 3, 2011

IDK about December 2011. But Duraclear used to be MUCH cheaper than Color Negative 8x10. I

Bob Carnie · Dec 4, 2011

I considered RA4 clear film for negatives on my Lambda, I decided to try Rollie Ortho 25 and now may move to Ilford Ortho 25.
I believe this product would work very well, I have used it for over thirty years in a commercial setting for backlight display work.
Someone here or on DPUG has tried it and said it was not sharp enough... Since the roll from Fuji(fujiclear) would cost over $2000
I was hesitant to try this route, but if there are workers here that think it is a good avenue I would be open to a group purchase and running some film for interested parties.
My platform is 30 inch roll and can give specs for each worker to try, length of roll is 164 ft, I also could get a smaller roll 20inch x 164 ft.

wildbillbugman said:
IDK about December 2011. But Duraclear used to be MUCH cheaper than Color Negative 8x10. I

wildbillbugman · Dec 4, 2011

Are Endura and Duraclear/ Duratrans the same thing ? It has been years since I worked with the later. A yahoo search turned up both. Whats the difference, if any?
I an realy interested in this project, although I cannot conceivably take on another project myself. What realy interests me is the possibility of making modern "digital" negatives without the "digital". These negatives use color to optimize UV blocking for processees like Carbon Transfer .
Bill

Photo Engineer · Dec 4, 2011

Bill;

The two are just roughly similar. The Kodak info sheet should show that the Duratrans or Duraclear have higher Dmax to fit the needs of the transparency market. Paper is made with lower Dmax. There is probably a contrast difference as well.

PE

T-grain · Dec 4, 2011

Ron, I checked the datasheets of both and, yes, there is some contrast difference.
Bill, my basic idea was actually to NOT run the paper/transparency through RA4 chemistry, but to develop only the silver image (of a single color layer) and to keep it instead-with and ordinary (low contrast) developer and ordinary fixer
I have an old box of RA4 paper somewhere-I might give it a try some of these days
regards

Photo Engineer · Dec 4, 2011

IIRC, the silver image of the RA4 products is very weak. You may be disappointed in that. The materials are designed to give high dye density with minimum silver.

PE

wildbillbugman · Dec 4, 2011

T-grain, Yes I understand what you want to try. My brain started wandering and I thought that, maybe Duraclear could be used to make the negatives similar to the principles used by people who make digital negatives. Here, the inks used in printers contain no silver and are low in D-max. Even the small minority of systens that use pigments instead of dyes (Epson K series and small brand copycats) are low in density.
Varrious colors are used to block the UV crititical to exiting,usualy dichromate. My interest is 3 color Carbon.
P.E., Inkjet negs contain Zero Ag.
Bill

Photo Engineer · Dec 4, 2011

It isn't the Ag Bill, it is the denity and contrast.

RA4 transparency materials were not built for use of just the silver image alone. The only way to find out is try.

PE

holmburgers · Dec 5, 2011

Howdy T-grain,

A very interesting idea for sure. However, it seems a bit like going from LA to New York by way of Anchroage... ok, maybe not that far, but...

The advantages that I see are the ability to use a safe-light and the cost, if indeed you can buy transparent RA-4 materials on the cheap. To me, it seems like that would actually be expensive... but I have no idea, I haven't looked into that at all.

I also suspect that a slide wouldn't be too well suited for a negative material. Can anyone comment on the typical density range of a color negative & and a color slide? If I'm not mistaken, a C-41 negative is fairly low in contrast comparitively and the RA-4 materials are tuned accordingly. But like you said, perhaps there could be some flexibility in the b&w developing stage.

The ironic thing is that one is using a color material to make b&w separation negatives to be used in a color assembly process. I'm no stranger to that though... using E6 screen plates to make color photos with b&w film.... but if the ultimate goal of these alternative color processes is to free ourselves from the chains of commercial color products, this wouldn't work.

But that's not meant to discourage you at all! It's clear that your brain is going to new places and that you're getting creative and highly original ideas.

I guess the crux of your suggestion is this; are tranparent RA-4 materials the cheapest panchromatic material (on a clear base) that you can get? If so, it just might be practical.

wildbillbugman · Dec 5, 2011

It isn't the Ag Bill, it is the denity and contrast.

PE[/QUOTE]

I thought that was my point.

Photo Engineer · Dec 5, 2011

Sorry if I misunderstood. My point was that RA4 materials are not noted for giving high density Silver images, just dye images. And therefore the density might be too low to be used in this context. IDK.

PE

T-grain · Dec 5, 2011

Photo Engineer said:
Sorry if I misunderstood. My point was that RA4 materials are not noted for giving high density Silver images, just dye images. And therefore the density might be too low to be used in this context. IDK.

PE

Ok, Ron, so there wouldn't be any problem if a chromogenic (RA4) developer is used and then a BW fixing, so a negative would be made of silver+dye?

Making separation negatives using RA-4 material?

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