Hi my dear friend @viking-ventures.
It took a while to do this answer because it had to prepare it.
There are some colors you can't find in the menu, like people, horses, sheep, cars, big buildings, and boats.
I found that by using my photos in Gaugan, :-) I'm sure there are more colors, but I'm looking for it, :-(
Well, I leave here what I call a Gaugan Palette, that was an idea invented by @shrazi.

Upload the first image brushes in the first menu below Gaugan App

Use this colors using the clone colors menu to get it as a bursh

Cloning these colors you can paint and in the end eliminate the top circles in the sky painting it with the Sky brush.
I will use this pictures in the next Gaugan post so that people can use it.
I hope this explains your question. :-)
Thanks for sharing such a beautiful painting.

😊

Edited( I had a mistake of a copy of a google translate. :-(
Changed.:-)