I always measure with my ruler, not the matt. I have several different colors, Downstairs on the cutting table I use for trimming my quilts after quilting, I have the standard dark green matt and also one that is yellow on one side and light green on the other. I find I get good visibility with these three color choices. Up stairs I have several colors including the standard dark green, blue, a light grey. Again, I can usually find a matt that makes it easy to see the edge of the fabric. Sometimes, I use different matts to cut during the same project.