bearisgray

Now I soak any unwashed fabric that I might use in HOT water for at least 30 minutes - like colors together - in case one has bad manners it won't hurt the other pieces of fabric. I smush them up and down once in a while just to move the water through the fibers.

I use sinks, kettles, large bowls, buckets, plastic wastebaskets to soak my fabrics. No point in using a whole washer of water when only a small amount of water will do the job.

If the water turns color, I isolate which fabric is donating dye to it - and give special attention to that piece.

Special attention - several more rinses until it stops bleeding color. If it continues to bleed, I dry it and return it to thestore (if possible) or discard it. No point in further aggravation. (There is a difference between excess dye - which when once removed, is no longer a problem - and unfast dye - which continues to lose color forever)

Then I wash the soaked fabrics in cool water with a very gentle detergent, gentle short cycle - I think it's the agitation that makes new fabrics look 'used' when they are washed -

At this point, I need to feel comfortable throwing all colors in to the washer together - just as they would be in a finished item. So until I am comfortable tossing that wet red fabric, and the wet black fabric, in with the wet white fabric, the red and/or black will need further attention.

and then dry until 'just' dry - I do not overload the dryer. I fold and put away until needed. Usually the fabric dries smoothly enough to not need ironing at that point.

Even with all this attention, occasionally I have had an issue when I sprayed sizing or starch on a dark red and a dark blue that I had previously washed.
(Both were by RJR, by the way - several years ago - Jinny Beyer/RJR fabrics may no longer have the color bleeding issues they once had))

Yes, this is a bit of 'extra' work up front - but I have enough stained fabric caused by migrating dyes to go to great lengths to avoid doing it again. I did not have great success trying to remove the unwanted dyes/stains.

PS: I am very aware that some of you see no point in doing this. This is about what I do.
I see no point in needing to use Synthrapol, Retayne, vinegar, salt, or color catchers with commercially dyed fabrics once the excess dye has been removed by soaking and rinsing and the fabrics washed.