I've done some printing on fabric, but have never done any that I felt would be washed. After a discussion with Aunt Edna about her's fading out with washing, I decided to do some trials. This print was done on white 100% cotton fabric and is a kaleidoscope effect of a photo taken last year in our backyard. This gives the same image many times on the fabric.
Strips were cut and the first strip was heat set using the iron and pressing the print under parchment paper. Just dipping it into the water caused the inks to release and fade.
The second strip was dipped into a vinegar/water (hot) solution. This didn't seem to fade as much, so when it was dry I put it back into plain water.... the inks released and it looked exactly like the first strip.
A third strip was painted using a fabric medium used to paint with acrylic paint on fabric... this was allowed to dry completely... dipped in plain water... with the same result. The inks released.
A fourth strip was sprayed with matte polyurethane.. allowed to dry... heat pressed under parchment paper... with the same result. The inks released.
So, it looks like the product (I will find the name and put it up) that you wash the fabric in before printing to make the inks colorfast is the only way to go if you are looking for colorfastness.