That's what SMPTE bars are for. You can set tint, saturation, and brightness with them. Contrast can be tough, although they do have a 100% white box.
I don't think you fully understand the DVI's brightness issue I'm having.
First, they are not reversed. (And if they were, calibrating would certainly not change that) They are both lighter than they should be. Enhanced should be darker than normal. Which it is. However, on mine, enhanced is putting out levels that where the normal setting should be (black at digital 16), while normal is even lighter. Black at 32, maybe? Calibrating the display to compensate with AVIA/DVE would certainly bring the levels to where they should be for viewing, but that's not the point. Video black is defined at the digital level of 16, and that's what you would expect the DVI output of the 3910 at normal to output. That's the display compensating for a problem with the source output. Like if the analog outputs had blacks at 20 IRE. Yes, you could lower the brightness on the display. But again, that don't make it right.
I could change the picture level settings in the 3910 itself. But why? You'd think the default, or the 0 setting should be fairly accurate. And actually I haven't tried this yet. It's possible that the brightness wouldn't go down far enough to fix it. Out of curiousity, I'll give it a shot next time I use it.
The question is, how do I know what digital levels are being output? As I said, I am basing it off the internal test patterns of my Iscan HD+, which have so far proven fairly accurate. Enhanced blacks come the closest to matching the black of it's brightness/contrast pattern. When I simply do a pass through of The DVI signal, the levels don't change, so it appears the Iscan is not screwing with the video levels much. And the black levels of the other Iscan inputs have matched fairly closely to the Iscan's test patterns, including the SDI input, which also uses the digital black level of 16. So I'm more trusting of the Iscan's level's being correct.
And here's another bit of evidence. I believe enhanced blacks should not be passing blacker-than-black. However, with my 3910 set to output enhanced blacks, somehow it's outputing a fine blacker-than-black signal. ????? Becuase the ehnaced blacks are where normal should be.