Article Response: You Think Your Film Was A Challenge

*What I learned:  1) I learned that you could use paint-on-glass animation.  2) I learned about an animation method that's new to me.  3)  I didn't even know this technique existed or how difficult it is.  **My Opinion:  1)  I liked learning about this style of animation and how not very many people have attempted it because of its level of difficulty.  2) I actually read the book The Old Man And The Sea so it would be interesting to see it animated like this.  ***Question:  Are there specific paints you have to use for this technique to work properly?  If so, what kind?