the controls that are available, seem to be specific to each input type. Maybe they're programmed in to each input board based on whatever the chip supports ?
I tweaked my DVI input again last night and turned the saturation down on the HT PC to 78 !!
There is a Colour control on the Component input (I have my OPPO DVD on that for the moment) and I set it to -8 on the display and the DVD colour control on full minimum (-9).
This all seems rather odd, because the HT PC was fine at stanadrd settings before using two different LCD 15" PC monitors (Philips and Acer). My Digital photos looked fine on them.
But now - viewing the photos on the plasma, the red & greens were 'way off'.
It suggests that the input on the Plasma is set to be too sensitive to the colour level.
(I don't remember having to adjust colour on the LCD PC monitors. I did setup colour level on my Philips 32" TV back in Switzerland (simply using the THX video test) and the settings worked fine across all inputs (a UK Dig Sat receiver, Pioneer DVD player (left behind) and the same HT PC which I brought here to the US), suggesting that all inputs were pretty consistent in their outputs. The Sat receiver and DVD player were connected using the European (21 pin) SCART connection which carries an RGB signal. The HT PC was connected to the TV by S-video.
Now I have the HT PC connected to the new plasma by DVI (which is digital RGB).
Results were the same using the VGA input from the HT PC, and there was also no colour control on that input. (There's a Input Level control but I don't see any effect from that).
If this seems to be a general 'problem' for the display across all inputs - maybe a ISF calibration would help to "push it down" so at least you get a correct neutral responce on the inputs where there's no colour control (like the DVI blade).
The output adjustment on the HT PC desktop (100 down to 78) has resulted in a pretty good picture but I'd prefer to "correct" the display device than tweak each output from each source, as maybe some sources it's not possible, like on a STB.