It sounds like the things you want to do could best be accomplished digitally. On the subject of skin tones, take a look at the following pictures. I took an RGB picture and made greyscales of each color (the same as filtering out the other two). What you probably need to do is use a combination of channels along with careful masking and control over the curves, contrast, etc. (Don't forget to take out any spaces in these urls; there is often one in the middle somewhere.)(posted 8749 days ago)Color: http://www.visto.com/?club=/visto/groups/fashion.jkantor&service=filep hoto&method=view&tx=n1y&filename=photo/Test+Shots/RGB.jpg
Green Channel: http://www.visto.com/?club=/visto/groups/fashion.jkantor&service=filep hoto&method=view&tx=n1y&filename=photo/Test+Shots/Green+Channel.jpg
Blue Channel: http://www.visto.com/?club=/visto/groups/fashion.jkantor&service=filep hoto&method=view&tx=n1y&filename=photo/Test+Shots/Blue+Channel.jpg