Interesting thread and the thoughts that have been expressed are pertinent. I have not worked with color in a number of years and the thoughts that I have on the subject may not be workable. However I will propose them anyway.Originally Posted by J.Leslie
Sharp masking should be as applicable to color as it is to my darkroom practices in black and white. Sharp masks are very precise burning and dodging tools. As such they are density initiated. By using lithographic half tone film contact exposed to the original camera negative, the appropriate interpositive (for dodging purposes) and second generation sharp negative (burning purposes) could very easily be produced. This would insure greater repeatability when a large number of the same print are required. Additionally this would allow very precise burning with color filtration adjustments should that be appropriate (albeit, the adjustments would need to be determined by actual trial in your darkroom and with your materials).
As an additional thought and aside from the conventional printing and possible sharp masking I have mentioned, it would seem that using lithographic materials that one could do color separation masking by producing the appropriate color separations much as the matrices are in dye transfer printing. I would think that if one were to do this that the color fidelity would be greater then any other process currently in use.
The downside to both of the processes which I proposed is that very precise pin registration methods would need to be employed. However one additional benefit would be that if one were doing Ilfochrome the method to do unsharp contrast masking would already be in place.
As I initially stated, these are my thoughts on processes that are not currently being employed, at least to my knowledge. It might be interesting for someone to pick up the banner and work these out.