Thanks for your reply ! This kind of advice is particularly useful for me because my English isn't perfect and thus we could find better names together.

The Lightness filter allows to change the luminosity of pictures or objects. Technically it is based on Component transfer Gamma. For example if you increase lights and shadows you obtain a more contrasted image like in the joined example file.

The Brightness filter allows to play with saturation vibration and eventually lightness of the colors (it can do it also with negative or inverted values). This one is based on a simple Color matrix. You can easily obtain very saturated pictures if you increase strength to 2 and decrease vibration to -0,5 (one half of the strength change) ; in the joined example I also decreased luminosity.

These filters are made to quickly obtain strong color effects based on very light code and suited to be applied before or after other filter effects ; as they are very sensitive the best is perhaps to begin with numerical entries (mouse wheel works very well).

Regards,
ivan