Great idea and fantastic implementation!! This is very well aimed to actual painters. Are you a painter yourself, or did you have any help from a painter?
I am a semi-pro artist and graduated from art school. But I had an almost 10-years break from painting. Some time ago I started painting again and decided to combine my painting and programming skills. Before launching ArtistAssistApp, I painted about 10 works with its help to make sure it's convenient and easy to use. Also, I asked a pro artist to make a few paintings with the help of the app to get the feedback. These paintings by a pro artist I used for promo videos in Instagram, YouTube and GitHub.
Awesome job