Welcome from Essex UK.
I have just given my Sister a queen sized jewel box quilt. The background was yellow and there are lots of oranges, reds and browns in it. I also gave her a box of colour catchers - Shout . I spoke to her the other day and she had washed it with 5 or 6 colour catchers and it had come out of the machine , and then the dryer, with no transference of any of the colours. Must admit I was worried about it before washing but she said that the colour catchers were only slightly coloured themselves. None of the fabrics had been washed before joining, and they had all been heavily starched. As it was not actually dirty, she had washed it on a 30 degree wash.
Hope that this helps.
Sue