What the Heck?! I don`t think anyone will be buying multiple copies of your book. The difference between $25 and $100 for a one time purchase is not a big deal! Anyone who is making emulsions must realize that $75 dose not buy a lot of AgNO3. I say Go For The Color. A color photograph of a gray scale image is only inappropriate if it misrepresents the actual image. A color reproduction of a warm tone black and white photograph can me more honest than a neutral reproduction of that image.
I am serious,for a change