SewMarti,
Yes, I recognize these as Jinny Beyer fabrics by RJR.
As a rule, I prewash everything, even kits. I had a few unpleasant surprises where colors bled and were hard to get out. Very dark colors and deep colors are the worse.
I serge the edges - barely skimming the edge of the fabric so I don't lose any fabric by serging or by fraying in the wash. Then I wash similar colors together with synthrapol and dry them in a hot dryer and then press them with a hot iron.
I also like Janet Stone's method of prewashing fabric. She wrote in her instructions for the last BOM: "Time preparing your fabric is time well spent. I recommend pre washing all fabrics.
Again, fewer surprises later on. I actually presoak my fabrics individually in white
plastic dish pans. I put the piece of fabric in the dishpan, fill halfway with warm water,
and let soak for about 20 minutes. That way I can see if a color is going to run. If it
does run, I keep soaking it until the water is clear. You can also add Retayne to the
water to stop the fabric from bleeding. Color Catcher sheets also work well if you
prefer to wash in the washing machine."
Finally, if it is a very dark fabric or a deep, rich color I might test it after pre-washing, to make sure it is okay. I test it by ironing the wet fabric between 2 pieces of white cotton to see if the color transfers to the white cotton. If it does, I keep working on it. It is a lot easier to fix it first than after it is in the quilt.
Judith