contrast masking with orange-maskless color neg

[MMfoto]

I'm wracking my brain to figure out if this would work... Using a color negative, like Rollei CN400 that does not have an orange mask, to make a subtractive color contrast mask for Ilfochrome printing. My thought is that you could contact print the original transparency onto the color negative with three separate RGB exposures to control the negative density for all three colors. You would then print the original in contact with your subtractive color contrast mask to control RGB contrast independently, with a single print exposure.

OK, now would it work?

 

[boyooso]

I would think that you would create neutral density.

You know that you can do this with B&W film, right?

Corey

 

[AgX]

Mmfoto,

Masking in colour photography is done to either correct unwanted colour absorption of the intermittent stage (might it be a negative or a transparency (positive) or to correct the contrast of the intermittent when printing on paper. The latter is typically done when printing from transparencies as they have a high density range.

This contrast masking is typically employed under the presumption that the colour balance is right. Thus a single monochrome negative mask is employed.
So, I don’t see any advantage in using a colour negative. That control of the single colours’ densities would be done via the light mixture of the enlarger. (Or am I wrong here?)
Besides you would also, as posted above, de-saturate the colour image.

To have full control of the primaries, which does not only mean density but gamma, you have to use three monochrome separations on which you gain full control over density and gamma. This is thus the separation way of colour photography as for it longest employed in dye imbibition processes as Dye Transfer, until digital processing achieved a comparable way of control.

 

[MMfoto]

...you could contact print the original transparency onto the color negative with three separate RGB exposures to control the negative density for all three colors... ...to control RGB contrast independently, with a single print exposure.

Neutral density, as with traditional pan film masks, would be achieved if the RGB exposures were equalized, and that's the point. Changing the relative exposures of the three seperate exposures, or exposing for only one or two of the primary colors would have the affect of altering both overall contrast and relative contrast of the three primary colors in a single mask.

I'm interested in this as an alternative to correcting color crossover by making three separate RGB exposures on the the final print with a pan film contrast mask placed in registration for a single exposure and then removed for the other two, while maintaining registration of the film, carrier, and print easel.

 

[boyooso]

Neutral density, as with traditional pan film masks, would be achieved if the RGB exposures were equalized, and that's the point. Changing the relative exposures of the three seperate exposures, or exposing for only one or two of the primary colors would have the affect of altering both overall contrast and relative contrast of the three primary colors in a single mask.

With Pan film you are not creating neutral density you are ADDING neutral density selectively to control the density and contrast of colors selectively.

I think with color film you would develop(create) the negative color of your transparency you would go grey or black very quickly. Though I've never tried it...

I'm interested in this as an alternative to correcting color crossover by making three separate RGB exposures on the the final print with a pan film contrast mask placed in registration for a single exposure and then removed for the other two, while maintaining registration of the film, carrier, and print easel.

Do you mean 'as an alternative FOR...' I'm just trying to clarify

That sounds like an insane amount of work! What sort of cross over are you having, there might be better ways to achieve your goal.

FWIW, it is possible to use dyes to retouch transparencies or contrast masks to correct of the cross over, but that is somewhat limited by the size of your original and percision of your brush.

Corey

 

[MMfoto]

Do you mean 'as an alternative FOR...' I'm just trying to clarify

Ouch, the grammer police is out!

Perhaps that should have read:

I'm interested in this for correcting color crossover as an alternative to making three separate RGB exposures on the the final print with a pan film contrast mask placed in registration for a single exposure and then removed for the other two, while maintaining registration of the film, carrier, and print easel.


OK, I cleaned that up. I think the original was accurate and conveyed the same thing, though this is clearer and more easily understood.

 

[boyooso]

I'm not the grammer police.

As I said, I wanted to make sure I understood. And to 'ME', 'I' understand your revised comments differently than I understood your originals.

So your reply is a good thing

Corey

 

[boyooso]

what sort of cross over are you seeing?

they might be process issues.

Corey

 

[MMfoto]

what sort of cross over are you seeing?

they might be process issues.

Corey

I'm not. This is as much a mental exersize as anything. I'm learning a lot about color theory and color printing and this is an interesting (to me!) idea I had regarding a hypothetical problem. I've spent the last few months reading everything I can find. I've been out of a darkroom for a few months, and when I get a new space set up (soon!) I want to do some Ilfochrome printing.

Thanks Corey.

 

[nworth]

You can make a simple contrast reduction mask using a black and white panchromatic film like Kodak TMX. The approach would be just like making one for a black and white negative, and a single mask would do the trick. I suggest you adjust the enlarger filtration for the best print you can get before you make the mask, and then use that filter setting to make the mask. If the mask winds up favoring certain colors, you can then make corrections and make another mask.

If you need to make color correcting masks, it becomes more complicated. Kodak used to publish a pamphlet "Color Separation and Masking," E-79, which gives good steb by step instructions. You may still be able to find it somewhere. The older color materials needed masks to correct for defects in the cyan and sometimes the magenta dyes. To correct for errors in the cyan, you expose the mask through a red (29) filter. Exposure and contrast controls can be tricky, but this used to be done routinely. In some cases, both contrast and color correction masks were required.