Color prints using BW paper

My friend and I have been discussing an idea we have had to make color prints using BW multigrade paper, and I wanted to run it past photrio.

It begins with taking 2 photos on BW film, one with a red filter and one with a cyan filter. Reversal process (or re-expose onto x-ray film or something) to get a positive image. Enlarge the cyan shot onto a sheet of multigrade paper through a yellow filter on the enlarger, so that it only exposes the green-sensitized layer of emulsion. Develop it with black and white developer, re-expose to green light, develop in Rockland Polytoner in a cyan color. Enlarge the red negative onto the paper (making sure both the film and the paper are aligned as they were before), develop in BW, re-expose, develop in polytoner as red, bleach, and fix. Basically a 2 color kodachrome.

Are there any issues in this? Or ways to make it simpler? Thanks

I am not sure whether the sensitizer dyes and development boosters in multigrade paper survive multiple steps of development. You could do a simple test: take an unexposed test clip of multigrade paper, run through developer, wash and dry, then expose with image and run through complete dev/fix/wash cycle. If this yields good images, your suggested process is likely going to work.

PS: I don't understand why you would reversal develop the two photos on B&W film. AFAIK you want negatives, not positives.

My reason for reversal processing is because I'm pretty sure that if I tried it as a negative, exposing the blue-sensitized layer would also expose the green-sensitized layer. If I reversal process, I can re-expose the green layer first and thus remove any light sensitive materials from it.

You mean that blue light would expose the green sensitive layer of multigrade paper ?

Yeah

I think I understand the reasoning behind your process now. A potential pitfall could be the emulsion layering in your stash of multigrade:

1. Ilford's paper has three sensitization types, blue, cyan and green. Not sure what their competitor's products look like, but Ilford's papers look unsuitable for your process.
   
2. If you do the green processing as described, this layer will completely block all light to all layers underneath it. Make sure, that the green layer is the bottom most layer. Maybe ask the paper maker ?

Many moons ago Kodak made Panalure a paper designed to make prints from color negatives. The paper was made with multiple layers each sensitized to a different color. However modern multigrade papers do not have individual layers but rather contain grains that are sensitized to more than one color. For the OP's purpose this is an important difference. There is no way to achieve what he wants with today's papers. It could be done using the dye transfer process but that isn't what the OP intended.

As I understand it, at least with respect to contrast response, multigrade papers don't have different layers of emulsion.
They have an emulsion where all the differently sensitized silver halides are mixed together in a single gelatin "soup".
So I am not sure that you will encounter problems with any layers masking other layers.

MattKing said:

As I understand it, at least with respect to contrast response, multigrade papers don't have different layers of emulsion.
They have an emulsion where all the differently sensitized silver halides are mixed together in a single gelatin "soup".
So I am not sure that you will encounter problems with any layers masking other layers.

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If this is correct and there is just one emulsion layer, then I'd say forget about it. The first dye plus developed silver will block most light. Since the OP proposed reversal processing, it will be silver or silver+dye everywhere, so no chance that blue will ever get good exposure. AFAIK Ciba/Ilfochrome had huge problems with the azo dyes embedded in the emulsion causing loss of light, now imagine the same thing with silver, too.

I think, it would be easy to make your own 3-layers paper. Middle yellow filter layer should block parasitic cyan exposition.

Study the old carbro technique. Unrealistic with today's materials, but once a successful if tedious way to make color pigment prints from bromide paper color separation.

Gerald C Koch said:

However modern multigrade papers do not have individual layers but rather contain grains that are sensitized to more than one color.

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I'm not sure I understand which you mean: A few types of grain, each type sensitive to one colour (range of wavelengths). Or grains where each grain is sensitive to more than one colour. The latter would make no sense to me, so I looked up at the description of the Adox papers (the Agfa MCC/MCP they continued under the Adox brand) and they are four emulsions coated together. I.e. one layer but distinct emulsions with different contrast and spectral sensitisation. I assume every vario paper is using the same principle.

As someone else said, who knows what happens when you develop, stop and then develop again. But assuming that all worked, then you'd still have the problem that each different 'colour emulsion' has a different contrast. Would be fun to match that. But maybe it could be done, since each colour is captures on its own film. The contrast of the film would have to be matched to the respective paper emulsion.

lantau said:

I'm not sure I understand which you mean: A few types of grain, each type sensitive to one colour (range of wavelengths). Or grains where each grain is sensitive to more than one colour. The latter would make no sense to me, so I looked up at the description of the Adox papers (the Agfa MCC/MCP they continued under the Adox brand) and they are four emulsions coated together. I.e. one layer but distinct emulsions with different contrast and spectral sensitisation. I assume every vario paper is using the same principle.

As someone else said, who knows what happens when you develop, stop and then develop again. But assuming that all worked, then you'd still have the problem that each different 'colour emulsion' has a different contrast. Would be fun to match that. But maybe it could be done, since each colour is captures on its own film. The contrast of the film would have to be matched to the respective paper emulsion.

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Portions of the emulsion are sensitized and then instead of the paper being coated in several layers the mixture is coated as a single layer. E pluribus unum so to speak.

I am not sure whether all the paper manufacturers use the same system. But Ilford published in their "Contrast Control" publication from 2001 that they coat a mixture of 3 emulsions, not three layers. All three emulsions have equal sensitivity to blue and vary only in sensitivity to green (one with next to none, the second quite a bit, and the third fully sensitised to green). But I am not sure if this would affect you experiment.

If I get you right, your idea is to take several pictures of a scene with colour filters and then print these on one sheet of B&W paper on after another and developing & toning each step with the Rockland colours. I do not understand the part of the re-exposing after each B&W development, is that related to the reversal idea or to the Rockland process?

Basically this sounds like a multiple exposure of the print in the enlarger, with the particular step of development and toning of each exposure individually. I guess it could work, unless there are reactions between the chemicals. And probably it will be quite tricky to figure out the contrast and exposure times, as the picture from the first exposure will probably have some effect on the second exposure.

Please do try and share the result with us. This sounds very interesting!

The re-exposure was for reversal, so that I can completely remove any green-sensitized grains before re-exposing to blue light. I am hopefully going to try this in the next week or so, whenever the polytoner arrives.

Hi Fagrid - we chatted about this on Reddit. Looking at the replies here, I'm guessing it's just testing time.

Thing is, even if you don't get what you're seeking, you may find something pretty cool. Curious to see what happens, I'm interested in alt processes that don't require a big digital negative - stuff that can be done with an enlarger.

Fagrid said:

The re-exposure was for reversal, so that I can completely remove any green-sensitized grains before re-exposing to blue light. I am hopefully going to try this in the next week or so, whenever the polytoner arrives.

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Thanks for the clarification. I do not see the benefit of combining this with a reversal process, but I guess I am missing some point here.
Please show us your results, your experiment sound very interesting.