Susie's Reply: In a word...YES! And you guessed correctly, raw canvas does need to be treated or preped for the watercolor to adhere to it without soaking into the canvas. Gesso is widely used as a ground applied to canvas to prep it for painting but regular gesso is non absorbent and doesn't work for watercolor. Daniel Smith developed a watercolor ground that makes it possible to paint with watercolor on almost any surface.
You'll find out more about this new product on the Daniel Smith website:
Just a little disclaimer: I don't work for Daniel Smith, I recommend their products because I believe in them and I am familiar with the products I recommend.
There is also a watercolor canvas made especially for watercolor by Fredrix. It's available in pads, stretched canvas, and mounted on watercolor boards. Most art suppliers carry this product.
I have experimented with painting on watercolor canvas and had fun trying new techniques. As I said it was fun, but not a suitable substitute for my signature style of painting. Try it you may like it!!!
Thanks for writing Kathy! Let me know how you like these products if you try them!