An LAB mode Blending Exercise

I've just finished reading up on the wonders of channel blending in LAB mode in Dan Margulis's book "Photoshop LAB Color". Thoroughly enlightening. I thought I'd have a go with this technique on one of my Boston holiday photos.

This first image is my original effort. The greens in the central tree look too yellow, and the magenta tree behind it is so yellow it's all but lost. The mistake I made was to boost both 'a' and 'b' curves to simply increase saturation. Boosting the shades of yellow in the green tree also boosts the shades of yellow in the magenta tree behind it, meaning they tend to merge. It looks better if I just boost the 'a' curve, but since there's green and magenta in both trees they still tend to merge together. It reflects what was there, but isn't too pleasing as a final photo.

This second image is my first attempt at using the channel blending technique to separate similar colours from each other. In this case I blended an inverted copy of the 'a' channel into the 'L' channel at 100% opacity in overlay mode. The difference is startling. Where the colour is green the light is increased, making the greens lighter. Where the colour is magenta the light is reduced making the reds and magentas darker. The effect is to separate the shades, making the greenish-yellows lighter and the reddish-yellows darker, but without messing up any of the other shades.

This isn't really the finished result. The image has lost its punch in the mid-yellow shades, and as a result I think I still prefer the original. I need to investigate this and learn how to correct it. But the principle behind the technique is demonstrated rather nicely.