I do use the color catchers. If I have intense color I will put several in the wash with the quilt.
I absolutely love Kaffe's fabrics. I am using a quilt made with his woven stripes fabric in the Optic design. I did not prewash the fabric. I then used those woven stripes with batik stripes for a quilt. I did prewash the KF woven and that was a big mistake as it took out the sizing and what ever so that when the 1/4" seams were sewn there was no end of slippage, causing me great frustatration as a new quilter who fell in love with a pattern. I learned to spray starch! and not to prewash.