Used Dell U2711 Measurement

[ChrisF]

Hi,

i have buyed a used dell U2711 monitor and have made some measurements because of visual color temperature differences between the top and the bottom of the display. In my feeling the color is at the bottom little warmer / yellowish / greenish and in the top of the screen cooler / blueish as on the bottom.

The measurements where taken with a Spyder 5. The monitor and the colorimeter warmed up >60min before started the measurements.

Please, read the table, do you think the monitor is okay or is the difference from top to bottom too high?

In the next days my ES-1000 spectrometer will arrive and then i want to repeat the measuremts to compare it with the Spyder.

Thank you very much!

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[ChrisF]

Hello again,

please find attached some more measurement results. This show the value for top, center and bottom of my screen directly after calibration, after 2hrs, after 24hrs and after 48hrs. The calibration target was 5800K, gimme 2.2 and 120cd/cm2 in the center.

I can see variability in the measurements for top and bottom, the measurements of center are constant. The top values shows little a cooler white point and the bottom values shows little warmer white point than the center.

What do you think about this?

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[Vincent]

Color (correlated) temperature to some known curve of “whites” is not a valid way of measuring color diferences.
Andrew Rodney (digitaldog)  have some free videos explaining it, and other sources have the same kind of explanation in text or video.

DisplayCAL allows you to measure screen uniformity with color distances to the center of screen, in an “absolute way” (color+brightness, deltaE) or “splitted” (trying to separate color tint from brightness drop like in delta C + brigntess percent difference).
Such test has a PASS/FAIL report related to ISO conditions related to color uniformity in screens. It is likely that a lot of non premium widegamut will fail on that test, includinng that old Dell, newer dells or newer benqs (just a few examples). Because of this you can use that deltaC “tint” diference to “subjectively” (out of ISO PASS/FAIL) evaluate if that screen is worth keeping or if you should try top return it. Measures will be objective, but out of ISO PASS/FAIL veredict it is “you” who puts a red line saying “it is aceptable”/”return it”. YMMV about what is good enough.

• This reply was modified 5 years, 3 months ago by Vincent.
• This reply was modified 5 years, 3 months ago by Vincent.

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