Layer blending is one of the ways I deal with color digital photos ...
I think how to do is not the key, the key is to know what is good ... This is going to require a professional eye.
Each film's color distribution is not the same, and the content is also before the difference, this time the role of the decision is not technology, but cognitive ...
First look at the original image:
Color to black, the world is not omnipotent the most universal \\\\\\\\ the best way. If there is, it is your eyes, your cognition. 50\\\\\\\\100\\\\\\\\-50 parameter, 100 unchanged, plus or minus 50 value change position, You will understand the effect of the channel on the image. As for what the most suitable parameters, the answer is: eyes, your Shong (you like that kind of graphics: strong contrast, elegant, etc.) (Editor's note: PS Chinese version open image-adjust-channel mixer)
That picture looks better.
Comparison of the last two graphs: