I think one would call it "colour burn." I did it over and over again varying the shades of blue and diddling in between with lightness and contrast. Purely seat-of-the-pants intuitive stuff. So I made my own drawing/digital painting of an original ship and background and am trying to get a near identical colour scheme and having one hell of a time. I hate it when I get what I want once and cannot duplicate it.

Thank you so much. I probably should have left it up, but I started freaking out over the attribution question. Life is too complicated for me and my tiny little pea brain.