I used Stabilo and Crayola markers and there was no bleed through. Pencils show up nicely as well, though the only flaw I saw with them was the impressions of the line work from the image on the other page came through to the image I was working on. Other than that, the paper is great to colour on and I found myself "zen-ed" out.
Here's a statement from Trisha herself in regards to her story, her books, and the love that goes into them:
"The books started from a dark place in my life. I was in a deep depression that was at a point that I almost took my life. I turned it into a positive by sharing it with friends and it grew from there. I love to doodle. I love to color. I love life. I did a lot of testing on the paper weight because my favorite medium is sharpie. That is also why I only put one picture per page. I do the spiral binding so the pages are easy to fold back. It also makes it easy to take with you if you are taking your book with you on the go. For example, waiting for the kids while they are getting out of school or at the Dr's office, the airport, etc."
Here's a sneak peek into Book 1---
I think it's safe to say colouring is ALL of our worlds ;)
Here's a list of all of her books that she has available for purchase:
Reviewed by Kourtney Ann Ferro