Welcome! The group is not very active now, but we have an active Discord. There you can get feedback for improvement. I'll also give you a couple of tips:
1) Provide links to sources. Even if the original author does not require it by license, he will be pleased
2) Write a description of your work, it will help to understand the context
3) And, personally (my specialty), before claiming true colors, please see this
- to understand, study such concepts as gamma correction, eye spectral sensitivity functions and color filters on spacecraft
So it's a complex topic, but even if you understand it a little, realism will increase a lot
Good luck!