Light output of LED and projector lamps decrease by time. To keep output same for every prints you need to adjust light output.
It is specially important for sensitive dental resins.
This modifier's unit is percentage and it effect color inputs on all profiles.
0 means no change to output. 80 means 80% increase in light output. -80 means 80% decrease in light output.
For example if profile render color is total white (#FFFFFF), -100% modifier make it total black (#000000).
It only calculated once before slicing of a plate and only effects newly generated plates from source files.