With hand painting fabric there is a front/back side to the fabric. I roll the fabric after painting but usually there are small air pockets that will create what looks like bubbles in the finished piece, this is considered the back.
Linen will always dye darker/more vibrant than any cross stitch fabric, then aida (14ct darkest, 20ct, 16ct, & 18ct dyeing lightest), followed by evenweave fabrics (usually not 100% natural fiber) dyeing the lightest. All opals will dye about 10% lighter because of the opalescent thread woven through it.
Sizes are prior to dyeing. There will be some shrinkage during the dyeing process.