This isn't a scripting question, so you'd be better off posting his in the general After Effects forum.
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However you can achieve the effect you're after using adjustment layers, effects such as Levels or Exposure, and feathered masks to select the areas you want to lighten.
Thanks for the answers, but when I use "ajustment layer" is works on all layers.
How to make a "adjustment layer" which only works on only one or unique layers?
example : same adjustment layer have effects on layer 2, layer 4 and layer 5.
That's entirely up to how you structure your project. You need to re-organize it and use additional pre-comps if necessary.
Pre-compose layer 2, 4 and 5 then add an adjustment layer or use masks as I demonstrated.