Mixing "as measured" and specified calibration values

[KLE-France]

Hi to all!

I’m relatively new to color management and very new to DisplayCal.

Before my question, here’s the nitty-gritty of my “Report on uncalibrated display device” (a  Dell P2414H):

Black level = 0.2224 cd/m^2
50% level = 38.55 cd/m^2
White level = 189.97 cd/m^2
Aprox. gamma = 2.30
Contrast ratio = 854:1
White chromaticity coordinates 0.3103, 0.3280
White Correlated Color Temperature = 6644K, DE 2K to locus = 5.5
White Correlated Daylight Temperature = 6646K, DE 2K to locus = 1.0
White Visual Color Temperature = 6435K, DE 2K to locus = 5.3
White Visual Daylight Temperature = 6610K, DE 2K to locus = 1.0

So, my question has to do with whether I should 1) run DisplayCal with the white point, white level and tone curve set to “As measured”, or 2) instead set them to the usual 6500k, 120 cd/m2 and gamma 2.2, or 3) maybe, mix them…

I’ve already run one calibration/profiling using the 6500 – 120cd/m2 – 2.2 approach. Everything seems fine, but I’m wondering if I can do better.

In the data above, my uncalibrated approximate gamma is 2.30 and my uncalibrated color temperatures are bouncing around the 6500 mark anyway (if I’m reading that correctly).

But, that white level at 189.97 cd/m2 is going to be waaaay to bright for my needs.

So, my core question is this: Would it be advantageous – or harmful – to set “Whitepoint” to “As measured”, “Tone curve” to “As measured”, but impose a “White level” of “120 cd/m2” (or potentially even lower)?

I hope all that is clear. I’m asking a question in a field that I don’t completely understand, so don’t hesitate to correct my thinking if need be (particularly if I’m misunderstanding the uncalibrated data).

Thanks in advance!

KLE-France

[Florian Höch]

Hi,

1) run DisplayCal with the white point, white level and tone curve set to “As measured”

That would be my usual recommendation. In your case especially, since it is expected the calibration will not need to change the whitepoint much to hit the daylight locus (already only 1 dE to daylight locus, which is a good uncalibrated result).

But, that white level at 189.97 cd/m2 is going to be waaaay to bright for my needs.

Set it to a comfortable level before calibration.

[KLE-France]

Hi Florian and thank you very much for this advice.

May I allow myself two follow-up questions?

1. Am I correct in understanding that the benefit of using “As measured” is that it leaves the monitor in its most natural state and thus most capable of exploiting what it is able to do? That is, with “As measured”, the monitor will be able to better cover the sRGB gamut, will be less likely to have banding issues, etc.?
2. Can I set the white level where it needs to be for serious photo retouching (i.e., low, implying in turn working with the window shade down), but manually increase the brightness of the monitor (using the onscreen adjustment) for less critical work (so that I can have the pleasure of an open window) without messing up color fidelity? The logical suite to that is of course that I would hope to be able to re-lower the screen brightness to where it was for serious retouching, and in so doing, re-establish the full calibrated/characterized state.

Thanks again in advance and thanks especially for your availability on the forum!

[Florian Höch]

Am I correct in understanding that the benefit of using “As measured” is that it leaves the monitor in its most natural state and thus most capable of exploiting what it is able to do?

1. Leaving whitepoint “As measured” simply means to use the native monitor white. In many cases, users do not have the need to match another reference white. I would still set tone curve to 2.2 so that you get the benefit of neutral gray balance even outside color managed applications.

That is, with “As measured”, the monitor will be able to better cover the sRGB gamut, will be less likely to have banding issues, etc.?

That can be a side benefit, although not necessarily.

2. LED-based backlights are usually stable enough that their color properties don’t change too much when adjusted, but I would definitely make sure to restore the calibrated state whenever you do anything color-critical.

[KLE-France]

Thanks again Florian.

Slooowly but surely all this color management stuff is getting clearer in my head!

[Author]

Posts