If it could only be that simple, I'll give it a shot. I'm working on a new technique (for me at least) to make a copy of the layer, invert it to the opposite color spectrum (Image>Adjustments>Invert in Photoshop) and then use the color blend mode. When you do this and set the Opacity to 50% the two layers pretty much wash each other out giving you almost a black and white version but the colors are all still there you just don't see much of them because of the opposite colors are blending evenly at 50% opacity. From there you can adjust the Opacity +/- to either side of the 50% to bring in the colors on opposite sides of the spectrum. I'm getting some great results with the washed out LED colors you get from poorly lit rooms. If I can find the time I'll work on these photo's again, right now I'm 3 music festivals behind at about 3,000 shots each festival!