New Post: cmyk image with only tones of black color

I was already on grayscale too and it worked. I also wonder if setting c, m and y channels to Quantum.Max with EvaluationOperator would generate same result without changing color type to grayscale. Also should we use Quantum.Max for min color value and 0 for max color value, i.e. c=0 for Color.Cyan constant. Is this usage with Quantum.Max right?
Thanks again