[Inkscape-devel] Brightness and Lightness

Hi all

The latest inkscape.pot update draw my attention on the terms "Brightness" and "Lightness". I supposed they were the same, but according to the filter names "Brightness, custom (color)" en "Lightness, custom (color)" in the menu "Filters" > "Experimental", there is a difference between brightness and lightness. Can anyone explain the difference, if there is any: is it a different concept, related to color space, different mathematical formula, ... ? Thanks a lot.

Regards Kris