Very, very interesting. The paintings you have selected for your post look very pleasing. I must admit when I had looked at art in the past I hadn't given much thought to what was used to create it. Of course I found some more aesthetically pleasing than others, but I never before focused on the materials used for the creation.
Most dont, kind of a lost idea. The proper use and knowledge of how and why the materials are made makes it much easier to pull off how it looks in your head ;)