Measurements

The NEC 3090 specification says:
Luminance Output – 350 cd/m2
Contrast ratio – 1000:1

Factory settings for brightness and contrast are 100%/50%
A usable range of brightness and contrast controls IMO would be:
Brightness 100% - 15%
Contrast – standard 50% is an optimum.

Below is brightness/contrast measurements summary.
Brightness control: 100% - 0%
Contrast control: 50%
Uncalibrated.