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I just started using DisplayCAL with Spyder5. After the initial calibration, I did a measurement report. I noticed that the display profile point is different from the whitepoint I set to during calibration. Here are the numbers from the report:
Display profile:
U3415W #1 2017-09-12 18-43 120cdm² D6500 2.2 F-S 1xCurve+MTXDisplay profile whitepoint:
xy 0.3112 0.3275 (XYZ 95.02 100 110.32), CCT 6599KMeasured whitepoint:
xy 0.3127 0.3291 (XYZ 95.02 100 108.86), CCT 6504KAssumed target whitepoint:
6500K daylight, xy 0.3128 0.3292 (XYZ 95.02 100 108.77)I’m trying to understand why the display profile whitepoint is almost 100K higher than the measured and assumed whitepoints . Is this normal?
An unrelated question, what should I set the Contrast control to for my Dell UltraSharp U3415W monitor? The default is 75 (out of 100). Will setting the contrast to 100 be better?
Hi,
I noticed that the display profile point is different from the whitepoint I set to during calibration.
[…]
U3415W #1 2017-09-12 18-43 120cdm² D6500 2.2 F-S 1xCurve+MTX
You’re using a matrix profile, and a requirement for the matrix is that the three primaries add up to white. If the display system is not very linear, this means the profile may not (and cannot) reflect the actual whitepoint due to this. The measurement report also confirms this.
An unrelated question, what should I set the Contrast control to for my Dell UltraSharp U3415W monitor?
The usual recommendation is to not touch contrast on LCD computer monitors. See the DisplayCAL documentation for adjustment tips of display controls.
On my Dell I displayed a patch with the upper levels of white (say 220 to 255) to assess how to set the contrast control. You increase the contrast until you see 254 clipping – then you dial it back a few clicks. Some monitors may also show discolorations before clipping the white so you may want to keep the contrast to a level where the display is still linear and the maximum brightness is displayed. But I wouldn’t expect that behaviour from a Dell. Make sure the calibration is disabled when you do so (right click on the profile loader on your taskbar and select “reset video card gamma table”: this resets the windows calibration to none)
Indeed, I would find out what the factory value is and start from there. Chances are it is the best value for your monitor.
I hope Florian is happy if I try and contribute to the question myself?
Thank you both for the response.
I borrowed a friend’s i1 Display Pro and the results seem to be better in terms of match between profile and measured whitepoint, but for some reason the assume whitepoint is now 6600K. The i1 Display Pro is so much faster than the Spyder5! It took about 40 minutes for the Spyder5 to complete the calibration, and only 10 minutes for the i1 Display Pro.
Instrument:
i1 DisplayPro, ColorMunki Display — LCD (generic)Correction:
LCD White LED IPS (WLED AC LG Samsung) <WLEDFamily_07Feb11.ccss>Display profile:
U3415W #1 2017-09-13 20-27 120cdm² D6500 2.2 F-S 1xCurve+MTXDisplay profile whitepoint:
xy 0.3119 0.3284 (XYZ 94.99 100 109.55), CCT 6552KMeasured whitepoint:
xy 0.3118 0.3282 (XYZ 95.02 100 109.71), CCT 6559KAssumed target whitepoint:
6600K daylight, xy 0.3112 0.3276 (XYZ 94.99 100 110.26)Calibrite Display Pro HL on Amazon
Disclosure: As an Amazon Associate I earn from qualifying purchases.Florian will certainly have an explanation for this.
However, what kind of precision are you looking for? I work in the cinema industry, in normal cinemas the allowed tolerance is +/- 0.006 and in Post Production houses it’s +/- 0.002.
I have a Dell myself and also a Display Pro (it’s fast, isn’t it!). They are nice but not professional devices. You are reporting a difference of 0.0007 on x and 0.0008 on y. Again, Florian will give you more technical background but from my perspective that a very good match!
Also keep in mind what I have recently discovered about metamerism: https://hub.displaycal.net/forums/topic/same-coordinates-different-subjective-white/
You may be struggling to get your monitor down to 0.00000001 to the target, yet your subjective white point compared to a reference monitor may be completely off.
However, what kind of precision are you looking for? I work in the cinema industry, in normal cinemas the allowed tolerance is +/- 0.006 and in Post Production houses it’s +/- 0.002.
Also keep in mind what I have recently discovered about metamerism: https://hub.displaycal.net/forums/topic/same-coordinates-different-subjective-white/
I’m not looking for high precision. I’m a photographer but not doing any professional work. I just like having accurate and natural colors. So I’m really only aiming for “good enough.” I’m also interested in knowing how far I can push my non-professional monitor.
The video about metamerism is interesting!
I hope Florian is happy if I try and contribute to the question myself?
Absolutely, you provided great tips on setting contrast, and healthy discussion is good. I’d encourage people to do more of that if anything 🙂
but for some reason the assume whitepoint is now 6600K
It’s rounded in 50K intervals. So, if the correlated color temperature of the measured whitepoint was 6550K, it’ll be rounded to 6600K, and the chromaticity of the assumed target whitepoint will be calculated from a daylight locus with that color temperature. Besides, correlated color temperature on its own is relatively meaningless (and a +- 50K difference doesn’t tell you much), if you want to assess the actual perceptual difference, look at delta E.
