A curious observation (contrast, RGB gain) on my ASUS
Posted: 12 Oct 2017, 14:11
I have an old(er) Asus VE248h where I just made a curious observation.
In the OSD (or with 3rd party tools using DDC/CI commands to control the monitor), you have levels for R, B, G (gain), ranging from 0-100, right.
However, these 100 levels for setting RGB gain are not actually applied, but in reality only 23 steps across this range. (I can check this visually by increasing G gain in the OSD, it always goes in little steps approx. 4 levels apart but nothing happening in between). (For example, I see a change at 28, then 32...and so on).
Now, NORMALLY this wouldn't be an issue.
The issue comes into play when you are adjusting CONTRAST, which I understand is also gain, but then for RGB combined.
Contrast however does full 100 steps.
As a result of this, there is an inconsistency in colour accuracy when you adjust contrast. Say, you gradually increase contrast and then observe how the display shifts repeatedly from having a slight pink hue, to having a slight green hue, from one value to the next and repeating. (Such as contrast 20 slightly greenish, 21-22 normal or pinkish, 23 again greenish etc.)
Say you calibrate the display at one contrast setting "ok", but then you change contrast to one of these contrast values, and your calibration is off again. I have NEVER seen such happening with a monitor! (I can now do a quick and dirty visual test with just slowly sliding contrast and see these colour shifts going on all across the range). (I am quite OCD when it comes to colour accuracy)
Has anyone ever observed something like this? Is it normal that some monitors although apparently providing 100 steps of RGB gain actually only provide 25 steps? (I am also not sure whether this affects also R and B gain, but with G gain it's just most obvious from looking.)
(Fortunately, this strange behaviour doesn't affect brightness values....and it is ONLY an issue if one happens to constantly change their monitor contrast, which NORMALLY doesn't happen anyway. I was just stumped that with this monitor I never got calibration (blacks, whites etc.) right because I change these values around all the time (eg. at night)...and now I know the reason for this inconsistency). Just think it's really odd.
In the OSD (or with 3rd party tools using DDC/CI commands to control the monitor), you have levels for R, B, G (gain), ranging from 0-100, right.
However, these 100 levels for setting RGB gain are not actually applied, but in reality only 23 steps across this range. (I can check this visually by increasing G gain in the OSD, it always goes in little steps approx. 4 levels apart but nothing happening in between). (For example, I see a change at 28, then 32...and so on).
Now, NORMALLY this wouldn't be an issue.
The issue comes into play when you are adjusting CONTRAST, which I understand is also gain, but then for RGB combined.
Contrast however does full 100 steps.
As a result of this, there is an inconsistency in colour accuracy when you adjust contrast. Say, you gradually increase contrast and then observe how the display shifts repeatedly from having a slight pink hue, to having a slight green hue, from one value to the next and repeating. (Such as contrast 20 slightly greenish, 21-22 normal or pinkish, 23 again greenish etc.)
Say you calibrate the display at one contrast setting "ok", but then you change contrast to one of these contrast values, and your calibration is off again. I have NEVER seen such happening with a monitor! (I can now do a quick and dirty visual test with just slowly sliding contrast and see these colour shifts going on all across the range). (I am quite OCD when it comes to colour accuracy)
Has anyone ever observed something like this? Is it normal that some monitors although apparently providing 100 steps of RGB gain actually only provide 25 steps? (I am also not sure whether this affects also R and B gain, but with G gain it's just most obvious from looking.)
(Fortunately, this strange behaviour doesn't affect brightness values....and it is ONLY an issue if one happens to constantly change their monitor contrast, which NORMALLY doesn't happen anyway. I was just stumped that with this monitor I never got calibration (blacks, whites etc.) right because I change these values around all the time (eg. at night)...and now I know the reason for this inconsistency). Just think it's really odd.