I'm not satisfied yet.
I realize the problem with the first piece was a failure to dilute the paint enough. When I started it over, however, I completely forgot about starting to layer with darker colors first- resulting in a bright stark contrast between the lighter colors and the black background.
So, in taking what I learned from the first two attempts, I started a new one. This time, I began with darker colors, and I diluted them well. What we have here is akin to a basic sketch. Over this, I'll continue to layer paint. I'll have to be very careful not to overdo it on pigment. Slow and numerous layers are key.
More to come.
See the original attempts here:
https://steemit.com/blog/@ellemarieisme/gunbot-university-comissioned-art