Andreas F.X. Siegert wrote: > I use "colprof -v -q m -a m -b n" > > Is there a way to influence the brightness? Hi, Yes there is, but you need to understand what you are asking of the system when you make a profile. The default ICC assumption is that you want the white of your test chart to be perfect white in the profile. If your test chart is exposed so that it is not at full brightness, then the profile will brighten everything up to make it so. You can modify the white point scaling using the -U parameter. Try a value > 1.0. See <http://www.argyllcms.com/doc/colprof.html#U> Graeme Gill.