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Hello,
For a long time I feel that my black shadows aren’t dark as they should be. I’ve made excuses to myself: “IPS blacks suck / The phone’s blacks are with dynamic contrast” and so on, but actually, I think there’s something wrong with how the gamma is calibrated.
I’ve noticed on lagom’s site, both on 10% and 25%, the gamma is 2.1 instead of 2.2. both on chrome and on edge.
It also fails this gamma test: http://glennmessersmith.com/images/adjust.htm. I can certainly see colors there.
I’ve made a test and deactivated the color profile loader and used NVCPL to lower the gamma to 0.81 and match the lagom test.
It certainly darkens the blacks without crushing shadows.
What am I missing? why is displaycal not calibrating the blacks gamma correctly?-“pixel density” plays a role here. Try to see that ramp with slightly closed eyes if you have a 24″/27″ FullHD screen (just an example)
-test is inteneded for sRGB displays : sRGB/R09 gamut
-finite contrast (aka black level) means that a random non OLED-like display cannot follow 2.2 power law. When you get close to darkest greys there is a choose to make: keep 2.2 as long as you can or deviate from 2.2 to make some kind of equally spaced transition between greys … or even deviate from 2.2. to keep grey neutral (since it does not matter for color managed apps, calibrated TRC will be stored so Photoshop will try to show true 2.2 in an AdobeRGB image as long as its limited precision bitdepth starts to make noticeable rounding errors).So a good 13″ FulIHD IPS/WVA/AHVA 1200:1 sRGB-like laptop would pass this test easily but a 24″ GB-LED 800:1 screen after HW calibration to native gamut may show strong cyan and magenta bars
-and first of all but last in this list: Did you measure actual gamma across the grey range?
I squint my eyes and it definitely merge at 2.1 at both 10% and 25%. Only at 48% it’s 2.2. I thought the whole point of a colorimeter is to fix a nonlinear grayscale which you can’t fix in any other way.
I don’t really care about accurate colors or graphic applications with color management, I only need to fix the grayscale which is bad by default on my monitor (2.05 approx gamma and especially on blacks)
I mostly care about games, pictures and videos. I need them to take a good grayscale where the gamma is fixed to 2.2 all over the grayscale.
I attach the measurement report. everything looks great, but the shadows could be darker, they look very bright to me for dark shadows and it makes games (which do apply the curve) very grayish and a bit washed out.If you do care about pictures or videos you need color management, it could be profile based transformatiosn like Photoshop or Firefox or LUT·D based like madVR or some kinds of HW calibration.
A lot of games clean GPU LUT so they do not have your custom profile VCGT content while in fullscreen. It is not “DisplayCAL” related.
HW calibration or some kind of in-game transformations (ReShade but IDNK how to use it) could help you with that. GPU’s LUT1D is not going to help you unless you play browser/desktop games.Your report shows gamma going doing under 2.2 from +/- grey 26 till grey 0. Take a look on what I wrote in my 3rd statement. Take a look in your profile’s calibration curves (DisplayCAL’s profile info app), the actual correction applied to your display.
Is it possible to make “grey 13” darker and what are teh consecuencies of doing it (take a look on calibration curves)? Did you configure DisplayCAL to do that? What do you want to do when actual light output approaches 0.1376 cd/m² (grey 0)? Keep in mind that you WONT be able to do an absolute power law because your light output for blak (grey 0) is not 0cd/m2. Is your card able to perform LUT dithering without showing “steps”/”coloration” in grey because of “height” in each display “native gamma” steps?
VCGT or LUT3D calibration can do a lot of things to improve a display’s response but when you try to emulate ideal 0cd/m2 output in power law gammas…there is a limit on what you can do.Games do take the GPU’s 1DLut, even in fullscreen. I’ve confirmed it with the test profiles. I only bumped into one game which doesn’t take the grayscale calibration. Also, all other apps take the grayscale curve. I can confirm this by just resetting the gamma ramp and then load it back, it definitely changes.
How can I configure displayCal to make it 2.2 all the way?
I’ve confirmed through nvidia control panel that it’s possible to see 2.2 on 10% and 25% and it doesn’t crush black levels and shows no real artifacts. the only problem is that doing so, makes 48% 2.4 gamma, instead of 2.2.
I don’t really understand all this technical stuff, I just want to know if it’s possible to make the gamma grayscale 2.2 all the way, cause that’s the main reason I’ve bought a colorimeter as it can’t be done any other way.“Your games” do use GPU LUT, I’ve not said “all” but a lot of them don’t.
Your answers about gamma should be expained in “Tone curve / gamma” documentation in DisplayCAL web.
“Display calibration curves” screenshot or dumping numerical values could help opter people to check if it is possible or if it is not posible to get actual 2.2 and neutral grey at the same time for a ~2.05 gamma display with unknown grey neutrality before calibration.I’ve just read “Tone curve / gamma” section in the documentation. I still don’t understand what I should do to get the gamma constant along all the grayscale.
I remember trying “absolute gamma” option, but it didn’t have any effect.You can’t, because near black, there is a compromise to be made: Either clip (unacceptable, so this is not done) or offset by the black level (smooth transition, but not the target gamma near black because it’s impossible without clipping).
But it’s not really clipping. when I test gamma 2.2 at 10% at nvcpl I can see all the black shadows, they are just a little bit darker, as I think they should be.
I can see it can make some banding somewhere, but I don’t mind banding if I get an overall more balanced picture.Of course it’s not clipping, that what I’m saying. Lets say you have a display with black level 0.5 cd/m2. That means the display cannot have a “perfect” gamma response, because that requires a black level of zero. It means gamma near black will be (has to be!) lower than the nominal 2.2, if calibrated to an otherwise 2.2 response, because otherwise, you would be clipping.
So, if I understand correctly, you’re actually saying that every monitor other than OLED can’t pass the 10% 25% gamma test on the lagom site?
I think that the results of that particular test are related to the poor performance of your display.
Between a low contrast with poor factory calibration AHVA gamer display and an OLED there are shades of grey. There are WLED sRGB IPS/WVA about 1200:1 (D65), W-LED PFS at 1500:1, VAs with 3000:1 (that is 0.04cd/m2 at RGB black=0 at 120cd/m2) and “pro” Ievel IPS with 1000000:1.
So the reason I can’t get proper dark black shadows is:
1. The factory native calibration of my display, which can’t be fixed even with a colorimeter
or
2. The 900:1 contrast ratio which isn’t enough for good blacks.
?2nd one + we do not know (not shown yet) which kind of correction does your display need in lower end (1st one, calibration curves in profile)
