thank you hborre for your tips.
i read already some rosity threads and googlepages of GC. (some time ago)
Working in former times with P7 / P8 and VSS (reading  bb's threads too)
i head resultst that was understandable.
With PPro2010, it looks like all has changed. 
I reduced my lights down for 50% or more and the image still looks washed out :(

does PPro2010 gc the input if i turn Rendersettings gc off and so on ...
arrrgl that drives me mad ...
srry if i complain, but the poser docu about gc is, to say in this way "very thin"