How to wash a quilt with Fabrico pen drawn blocks for first time
 

We have created a quilt for our grandson where every family member drew with Fabrico pens on a block. The quilt maker asked for us not to wash the blocks before sowing. All the blocks were ironed before the quilt was made.

The quilt now needs its first wash and we are worried that we might ruin it.

I have some Retayne, special wash powder and colour catcher ready, plan to use the bath tub, but would like some advice on the best method please.
What to do before, during and after the wash?
Do I spray Retayne fixative over the pen blocks before the first wash?

If this was me the first thing I would try is making dummy blocks using the same material and pens - iron well as your blocks have been and then try the variations on washing you have suggested.

Look at the website for the type of pen you used. That should tell you how to set the ink.

I think that's a good plan. It's what I would do.