Synthrapol lifts the color from the item and Retayne sets it. I have both and have used them both, and I generally include washing instructions with gifted quilts....In most cases a cold wash and a cooler dry. Understand that very few people are going to line dry....most will use a dryer. I looked up both Synthrapol and Retayne and the computer to understand the difference......good luck with your squares. Once made, one hates to give them up