I started soaking like colors together for several hours now (per Vickie Welsh) after a jimny beyer dark red and a jinny beyer dark blue bled when I sprayed sizing on them. These fabrics had both been machine washed in warm water.

I have learned that it sometimes takes several hours for excess dye to release.

wthe the soak8ng method i can figure out which piece of fabric has bad manners.

Synthrapol will not STOP a bleed. It is designed to keep the dye particles from adhering to other fabrics. If you want to wash a quilt and are worried that some of the fabrics might bleed into other fabrics in the quilt, use Synthrapol. I have had very good luck with Retayne when used according to directions. However, you also need to consider the quilt usage, how often it will be washed and who will be washing it. I don't think I have ever washed a quilt in hot water--dry on hot in the dryer--but not hot water wash. Have you?

Mine was like your darkest sample thru 4 washings. I've been doing some reading and there were suggestions that you use Synthrapol after Retayne so that the color doesn't begin bleeding if the fabric is washed in hot water. I have the backing all starched and prepped for quilting which I need to start on so now I'm not sure what to do.

When all else fails, I either give up on the fabric or try a round of heat treating. With a pyrex or large microwavable (preferably glass) bowl, dampen fabric first and then immerse in water. (Edit -- if using plastic I would not use for food use after dying use) Wrap the top well with plastic wrap, and nuke at high for 20 minutes...then I let it cool down until I can touch it, do a rinse (maybe with a small amount of original dawn) and that doesn't work -- time to move on!

I think this was the thread and someone was talking about red flannel. Not only does it often bleed excessively, but it also "crocks" that is, rubs off on other fabric. If you have any long term in your stash, I suggest wrapping it in tissue paper.

This picture is of a fabric I gave up on. Both patterns were released at the same time/same line and I used a blue with no problem. I did a standard pre-wash but no color captures, or tests, and it was the one time I ruined a quilt with bad fabric. Turned the sophisticated silver grey/blue/white/maroon into baby pink :(

So the dark piece has been washed a couple of times before I stopped. The Orange piece started out the same color and after 7 or so washes, still runs like a thief in the night...

Bleeding
 

I had a 6 yard cut of Moda, deep maroon red. It blead like crazy...I kept washing it, still a heavy bleed. Tried color catchers, vinegar. Nothing worked.
I called the quilt shop, they called Moda. Moda said they had a large run of that fabric where the color was never "set" in the process.,they said there is nothing that I could do myself.
they sent me fabric in the same color that did not bleed. What a hassle.
I often wonder if there hundreds of quilters that still,have the same bad fabric in their stàsh....and the years are clicking by.....and it will be too late for Moda to do anything for them when they discover the bleeding issue.

I have a piece of beautiful and expensive aqua blue Shweshwe that is still bleeding. Tomorrow, I am going to try Retayne. If that doesn't fix the problem, I guess I'll eat the cost. T bought the fabric for a bag but I can't risk it getting wet from rain and bleeding over a piece of clothing.

eeeeeeeek!!! What a mess that would be!
GOOD LUCK!