What is the "black" slider for?

[Wayne_Sutton]

@micha

You control the black and white points only with the curves?

personally yes but it is simply a question of preference. Rawpedia has a description of the black slider if you prefer to use that: Exposure - RawPedia

@micha

And about the white point: I found the slider in RAW:

Again, there’s a description of the slider function in Rawpedia. http://rawpedia.rawtherapee.com/Raw_White_Points which states that:

Blockquote
It is unlikely you will ever need to use the Raw White Points tool other than for diagnostic purposes.

This has also been discussed on the forum: If I want my whitest whites to be 255,255,255 - do I adjust the RAW white points?