Is possible to use this "map" as a mask? (After Effects)

Question

I'm creating animations like the hearthstone golden cards,and I'm tired of masking everything bit by bit. I know that the hearthstone team used masks (with colors) in order to make the animations,they used a map of colors that was telling the after effects where to apply the effects and where to ignore the effects. Exemples:

Image 1:

Mask 1:

In this case,the blue area had a particles effect,the yellow/green had a glow and the redish was some rotating light effects.

In a nutshell: How can I tell after effects to make some effects visible only in a certain spot using a color map?

Answer 1

Create an adjustment layer above the base image and apply one of the effects to it (you will have to do this whole process several times with one effect per adjustment layer). Add the colour mask layer above the adjustment layer and use a key effect (Effects>Keying>whatever…) to make the relevant colour for the effect transparent. Set the track matte for the adjustment layer to "Alpha Inverted Matte the colour mask layer".

Using an alpha inverted track matte will make the adjustment layer opaque only where the Alpha Matte is transparent, so the effect will only be visible in the areas defined by the relevant colour. Note that when you apply the track matte the layer that is acting as a matte is made invisible (eye icon switched off).