Originally Posted by Glassquilt
Like others my first thought was possible color blindness. We had one female customer who was color blind, very unusual for a woman. But she saw value - grays, blacks & white. She had to trust other to pick her colors for her.
Has she asked for help? Has she commented on the appearance of some quilts? Perhaps wholecloth quilts or monochromatic quilts.
Value: You can make a black & white copy of fabrics and study how light/dark they are. I sometimes scan them and change the jpg to grayscale.
Using the grey scale to determine value is an excellent idea. That's how I taught value to young children in art classes. I also taught them to squint at a picture (insert "fabrics" ) to see which ones are light, medium and dark. I called them "the 3 bears" to help them remember the concept. The 3 bears works well for picking patterned fabrics too.