This is a chronic problem for me. A number of solutions have been offered elsewhere on this forum but none were completely satisfactory. For anyone else struggling with this issue, I would like to share a great answer to the problem-- if you are in the habit of stretching your paper. I had soaked my paper and stapled it to my Gatorboard when it occurred to me that it was silly to let it dry just to turn around and re-wet it before painting. I did let it sit for one hour but then added a bit more water on top and did my first wash. It worked great! I hope someone else finds this helpful.