This scene is copied from a photo I took of the Colorado River in the Rocky Mountains. I think it was a little east of the Upper Gore Canyon, after the canyon opens up into a relatively broad expanse.
The five paints used on this were made from scratch with dry pigments. The palette can be seen on Instagram here. The yellow and ultramarine were only used a little. Mostly it’s zirconium cerulean, red ochre, and mars black. Because the cerulean was weak in mixes, mixing a large amount of it to the mars black produced a useful cool black that was easy to handle and wasn’t overpowering. The granulation from both of those and the red ochre did make it a little difficult to really get the smoothness of the water or the ice in the foreground. This was painted on the back of a piece of 140 lb cold press Arches paper, which I’m starting to prefer over using the front of the paper.