Curves -- HSL, be able to adjust the S and the L for all curves simultaneously.

[mpstaton]

Probably like a lot of amateurs that use Affinity, I download a lot of art from commercial libraries and modify them. I'm not that good at drawing them myself, and it takes forever anyway.  

I'm always ending up with images where I need to batch change colors.  The Select Same Fill was a game changer for sure.  However, a lot of this art has dozens if not hundreds of colors.  I just want to brighten them.  

(Note, it would also be cool to be able to select curves that are DARKER than a certain range, or LIGHTER than a certain range, and then change those in specific, or actually just delete them (as I'm usually trying to remove backgrounds anyway.)

Here's an example of art I need to modify.