Basically what I am trying to achieve is illustrated in this Image:
I got a background color (R:19 G:25 B:37 or #141A25) upon which I want to layer another color at 80% alpha to get a target color (R:52 G:96 B:29 or #415C1E). I am looking for the specific RGB values of that 2nd color I am layering over the background and how to calculate them.
While I can get there through approximation and messing about (in the example it is only 98% there), I'd like to know how to get there through calculation rather than wasting 5+ minutes shifting color values.
Thanks in advance for any help! :)