External proc amp: changing levels, legal range 16-235?
 

The Datavideo DVK-200 has a proc amp and allows one to adjust the brightness, contrast, tint, and color saturation. When I adjust the brightness or contrast while looking at the VirtualDub1911 histogram (after cropping, etc.) I notice that the histogram level never goes into the left or right red zones.

Question #1: Is this normal behavior for any external proc amp? Do these devices somehow prevent illegal levels, even on super bright scenes? I'm a newbie to external proc amps and just trying to understand.

FYI, my VirtualDub1911 Levels are set to Brightness 147 and Contrast 106 because I have an ATI AIW 9600XT and Sanlyn recommends these settings for this capture card.

Question #2: Does one always need to set the VirtualDub levels to these values, even when one uses an external proc amp? Or should the levels be at 128, with all adjustments in the external proc amp?

Can you make it go into the red zone without the proc amp in-line? I would expect the capture device driver to be what's limiting the output to 16-235.

For question 2, I would set the capture device levels to their defaults and then leave adjustments to the external proc amp.

Yes, I can make output go into the red zones using the Levels screen in VirtualDub1911. I just can't seem to trigger the red zone when adjusting the brightness or contrast on the external proc amp.