by Adriano Marzano de Carvalho
Upd 30/09/2016: when on very dark env (no light), it does not change brightness
Upd 27/07/2016: bugfix as stated by Thursen
I decided to provide this new flow to those who wanted my previous flow (Google Photos Brightness - http://llamalab.com/automate/community/flows/1879 ) to support other apps.
Basically you'll select apps you want to have different brightness settings, define the value and done. Whenever you open one of these apps, it'll change brightness. When you close, it'll set it back to normal.
Rate and review within the app in the Community section.