One of my goals for 2020 is to improve values and colors in Photoshop, especially with metallic reflections. I' ve been using an old 2012 sketch of a Brutix-like ship (from the Eve Online game) as the Gallente curvy style and shiny metals with green hues are good for this exercice. I'm calling it done as I could just keep tweaking it forever. I have learnt a lot doing this exercice and while I could spend a few more hours on this I feel like it will probably be more efficiently to keep improving that subject on a fresh new ship.