Brightness and contrast
With the brightness we are immediately faced with a surprise: the Samsung C49HG90 does not exceed 263 cd/m². You might be thinking that this will hurt its HDR capability - but you would be wrong, because in HDR-mode ('High brightness') the monitor is able to produce a total of 654 cd/m², by far the highest measured brightness that we have ever seen on a monitor. That is why this graph does not matter all that much - for regular use 250 cd/m² is more than enough, if it would be more than that we would consider it undesirable.
Moving on to the minimum brightness: white with only 15.5 cd/m², at least you do not have to worry about being blinded in a dark room.
For black at 150 cd/m² of white we note 0.06 cd/m² - not an extremely exciting value, because aside from the LG all competitors have a va-panel. Va is the new ips, you read it here first. On the other hand, the maximum vlaue of black is the lowest. As a colleague said: it is not as pretty as the black of my oled-television, but it is certainly pretty black.
Depending on how we perform the measurement, the contrast is extremely good to excellent.