This is a study of 4 skies in my sketchbook using different blues as a base. All 4 were done wet on wet and each one is about 3″ x 5″. The first one is Cerulean Blue with Burnt Sienna highlights – Holbein Watercolors. The upper left is French Ultramarine with Cadmium Orange highlights that are more streaked- Utrecht Watercolors. Bottom left is just Phthalo Blue Holbeiin Watercolor. The final study in the lower left is also Phthalo Blue with color removed with paper towel while still wet. This is a technique that I use often for skies. The paints do not mix or flow as well on the Alpha paper as they would on true watercolor paper.