The monitor has 90% brightness and 80% contrast by default. I lowered both to 74% to achieve a 100nit brightness of white. Color gradients are reproduced without banding at any settings. Lights and darks are all distinguishable at any settings, too. The monitor regulates its brightness by means of pulse-width modulation of the power of the backlight lamps at a frequency of 240Hz.
The average uniformity of white brightness is 6.9% with a maximum of 18.2%. For black brightness, the average and maximum are 6.3% and 15.5%, respectively. The average values are not every good, but the rather low maximums indicate that there are no conspicuously brighter or darker areas on the screen.
The gamma curves are good at the default settings but differ somewhat from each other as their values of gamma differ.
The curves change but slightly at the reduced brightness and contrast.
As opposed to many other monitors, this model doesn’t have too much contrast at the maximum settings which would be indicated by a characteristic bend in the right part of the diagram (meaning that light halftones are displayed as white). The VB191T has this bend in the red curve only. The other curves are very close to the theoretical curve. The overall setup quality is even better than at the default settings.
The temperature of grays varies within 500K in every mode, being warmer on white. This is good as every user can select the color temperature that suits him best.