For prevention of bleeding fabric. I'm so confused. What exactly is the difference? How do you know which one to choose?

I believe Retayane helps set the dye and Synthropol suspends it in the water, to keep it from settling into the fabric.

Synthrapol grabs the extra dye molecules and suspends them in the wash water, then they go down the drain. I dunno about the other one.

Is this fabric you dyed, or red from a store? I use Synthrapol when I dye fabric, works awesome.

If you have a piece of fabric that is bleeding, you would use Retayne to set the dye. You would not use Retayne in a load with several different colors.

If you want to wash a quilt and are afraid something might bleed, wash in Synthrapol. Synthrapol will suspend unset dye particles in water so they can be rinsed away instead of settling into other fabrics. I don't prewash my fabrics, so I always wash a new quilt in Synthrapol. (I do test fabrics I suspect might be "bleeders".)

You would never want to wash a quilt in Retayne because it could permanently set a bleed into other fabrics.

Just be aware that Synthrapol may not be able to handle a red (or other color) fabric that is bleeding copiously. There's only so much it can do. If you suspect a fabric might be a heavy bleeder, test it before putting it into a quilt, and wash it in Retayne if it bleeds so that the dye is set.

Someone on this forum had made a Christmas tree skirt. Her husband accidentally spilled water on it and the red fabric bled into the white. Even with Synthrapol, she was not able to change the white fabric back from being dyed pink.

Synthrapol can sometimes remove existing bleeds from a quilt or an embroidery piece but that is more iffy.

interesting topic, will follow this thread

Prism is on the right track...if they dye molecules have already attached to white or "some other fabric" then it's there. Synthrapol deals with dye molecules that have not found a permanent home yet.

Synthropol suspends it in the water, to keep it from settling into the fabric.

Synthropol is cheap so I'm thinking it's a better value then the dye catchers sheets for all laundry. The directions say 1 to 2 teaspoons per load.

Where do you find these products? I don't think I have ever seen either one of them. We don't have any LQSs around here so far as I know.

^^^I get Synthrapol from Dharma Trading Company. But, I did see it in a local art store as well.

This is a better buy:

http://www.dharmatrading.com/products/syn.html