tip one
Go gray
One of the easiest ways to get better tonal gradations from a black and white image is to create a duotone with black and a match gray.
tip two
Quadruple quality with quadtones
Two hits of black, a match gray for tonal range and a fourth ink for whatever color tint effect you want to achieve.
tip three
Show your color bias
Use an original black and white halftone to make CMYK plates. Then manipulate each of the ink passes to “bias” the printed image. You can achieve rich, balanced color, or get different tint effects using the process colors.