Do you PRESS or IRON your Yardage before starting to cut for piecing?
Being a rank amateur myself, I have been doing a lot of stuff on white background with some very bright solid colors. Fortunately, my cousin, who has a quilt shop in Oklahoma, forewarned me about the bleeding of fabrics, especially bright colors. Otherwise, I would have had a ruined quilt that I worked very hard on for several months!
I just started a new project -- a baby quilt -- again using a white/white on white background. And, yes, I washed all the fabric and used a dye fixative to set the dye in the bright colors. I absolutely breaks my heart to think I might put all that effort into a quilt and it be ruined by bleeding dyes in fabric! IMHO, it's worth the effort although it does take a lot of time.
Jeanette Frantz