Adjusting greyscale using form fields when printing.

The backgroud color of an annotation or form field can be controlled with a script. 

So for example, this validation script for a text form field controls the grayscale of a form field named "ColorPatch"

Gray scale values are between 0 and 1

if(!isNaN(event.value) && (event.value >= 0) && (event.value <=1))

{

    this.getField("ColorPatch").fillColor = ["G",event.value];

}

This technique can be extended to include shading for other color values.