"The Luminosity blending mode applies the luminosity (brightness) of the blend colors to the base image while retaining the hue and saturation of the base image. Luminosity is the opposite of the Color blending mode."
Increasing the ContrastYou can increase the contrast with this Blending Mode very easily and in a really natural way. How to do it?
Add new Black/White Gradient Map on the top of your layers and change the Blending Mode on Luminosity.
Adding Lights and ShadowsThe next thing how I start to use Luminosity Blending Mode is to create lights and shadows in my manip. According to me it makes more beautiful colors then using grey layer with Overlay Blending Mode. Grey layer sets to Overlay tends to oversaturated the colors.
When you´re adding lights and shadows throught Luminosity Blending Mode you have to paint with black and white and really low opacity (arround 3%) or with different shades of grey.
Other Tips From The InternetMethod used to improve tone: A simple way of doing this with skin is to use a channel mixing layer set to mono the green channel +100 (as attached). Then set this to Luminosity blending mode. This often improves the skin tones.
One of the biggest uses for the Luminosity Blend mode is during sharpening. Sharpening can produce color halos. By sharpening on a separate layer and setting the blend mode of the sharpening layer to Luminosity, only the luminosity of the image will be sharpened. This will eliminate any color halos.