It is acrylic and watercolor layering just like all the other recent paintings. I am hooked. The way the sunlight glistened as it rolled back into the ocean was irresistible to paint. Painting on yupo makes it so easy to remove the color in the receding lines, no need to frisquet lines. No pre-planning of the white areas at all. I painted the background colors as close to the desired lighter colors as I could without being too rigid. I like when the colors bleed into each other which gives a surprise area or special coloring not obtained if I control its placement. Then I remove the white areas. Add the watercolor in the medium to dark spaces with a back and forth dance of color until I get it just right. The fun part is "there's no worries"...I wipe off or use a brush to sculp the watercolor areas to form shape to get the right color / the right shape and the background is undisturbed. I must admit there is a technique to it but truly its just painting as if you were adding colors to regular watercolor paper.
Letting go and just paint. It is so freeing! This must be why I like it so much.