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When it comes to color management and calibration, reading in official/unofficial sources, there are different oppinions telling that the native display gamma value can be left "as is" = "native" (2.43 measured in my case)

OR,

on the other hand, gamma value could be set at 2.2;
How can I approach this, which is the "right" seein color, at native monitor gamma value or other value (e.g. 2.2)? if the gamma have any influence in the viewing process excepting all the other variables (room light condition, color temperature, etc considering these the same in both cases).

—Official source: page 96,97 of this book for example.

—Another source Argyll.com:
Adjusting and Calibrating Displays
By default, the brightness and white point will be kept the same as the devices natural brightness and white point. The default response curve is a gamma of 2.4, except for Apple OS X systems prior to 10.6 where a gamma of 1.8 is the default. 2.4 is close to that of many monitors, and close to that of the sRGB colorspace.

—Another one dispcalGUI documentation:
Why has a default gamma of 2.2 been chosen for some presets?
Many displays, be it CRT, LCD, Plasma or OLED, have a default response characteristic close to a gamma of approx. 2.2-2.4. A target response curve for calibration that is reasonably close to the native response of a display should help to minimize calibration artifacts like banding, because the adjustments needed to the video card's gamma tables via calibration curves will not be as strong as if a target response farther away from the display's native response had been chosen.

Of course, you can and should change the calibration response curve to a value suitable for your own requirements. For example, you might have a display that offers hardware calibration or gamma controls, that has been internally calibrated/adjusted to a different response curve, or your display's response is simply not close to a gamma of 2.2 for other reasons. You can run “Report on uncalibrated display device” from the “Tools” menu to measure the approximated overall gamma among other info.
...

That's why I am still confused.

  • Possible duplicate of What is the standard gamma value? – Michael C Dec 14 '15 at 21:11
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    Actually I'm not looking for a standard gamma value. As I've explained above, I'm looking more for an elaborate answer, that could confirm the native gamma value usage in different cases (like this one 2.43 over 2.2 not under the standard value). – user124853 Dec 14 '15 at 22:33
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Setting display gamma to 2.2 or sRGB (in LCD OSD settings, that is) will make it closer to perceptually uniform (i.e. efficient for be used by human) and also make 8 bit images with gamma 2.2 or sRGB expose less banding (bigger colour depth) when viewed at 100%.

However, there is a problem, at least with DisplayCAL: creating profile for gamma 2.2 means that 1D LUT will be created. This 1D LUT can be applied in two ways:

  • using videocard LUT (most oftenly 8bit -> 8bit)
  • using display internal LUT (may have much bigger internal precision like 8bit -> 14bit)

Here comes the problem. Assume that you have an 8bit LCD which does not have gamma correction at all (or does not allow the gamma to be set enough closely to taget) and also does not use editable internal 1D LUT. If you calibrate your LCD for gamma 2.2 the DisplayCAL will make your LCD loose colour depth because it does not offer any interactive gamma adjustment. Therefore your LCD won't even be 8bit anymore (more like 7,5bit, for example).

If your entire workflow is 16bit there is zero sense in creating 1D LUT. However, since most LCDs have extra contrast, you may set your LCD gamma to compensate for it BEFORE profiling and then create profile for gamma "As measured".

Creating 1D LUT for video card (8bit to 8bit) will only cut your colour depth.

  • interesting feed-back thank you.My pretty old Belinea P-MVA, have—according to the technical feaflet—24-bit (which, as far as I understand it's 8-bit/channel).Indeed there is no internal LUT possibility and also there is no interactive gamma adjustment. At this point I'm pretty confused, but I suppose, you're trying to say that if our workflow is at 16-bit/channel and the monitor is limited at 8-bit/channel, the calibration process is useless—that's the point? Also, in your oppinion, should I let the monitor gamma value at 2.43 measured in my case?thanks – user124853 Mar 15 '16 at 21:30
  • @user124853: yes, in case when you cannot tune LCD you should profile for native gamma. If you are working with 16bit images you won't loose anything. – Euri Pinhollow Mar 16 '16 at 5:29
  • make sense somehow but, Is there any possibility to visually check if the monitor allow the gamma to be set enough closely to target? running a measurement report after the dispcalGUI profile was loaded (assuming that we choose an sRGB 2.2 profile) I guess that could be shown any LCD limitation, am I right? the LCD also allow to be set at sRGB but if measure this hardware setting, doesn't look like dispcalGUI sRGB setpoint. Also do you have a source that approach much deeply this subject please? – user124853 Mar 16 '16 at 8:41
  • @user124853: yes, you are right, you may review the tone response curves to see how bad your LCD is. You may open any profile tone response curves and compare them (just be sure to select proper viewing settings below). Example. The bigger slope around 0 means that extra contrast is compensated. Here is manual for ArgyllCMS, the basis for Dispcal. Most LCDs are very bad in conforming with sRGB, both white point and gamma are quite wrong. – Euri Pinhollow Mar 16 '16 at 10:33
  • thank you, so I guess that we are getting back at this "The default response curve is a gamma of 2.4, except for Apple OS X systems prior to 10.6 where a gamma of 1.8 is the default. 2.4 is close to that of many monitors, and close to that of the sRGB colorspace." mentioned in AgryllCMS documentation, and above in the main question; so in my conditions I should stick to the native display gamma value. – user124853 Mar 16 '16 at 12:52
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My opinion is there is only one answer possible. Gamma 2.2 is, was, and will be the standard. It is the standard for sRGB in our JPG, and Windows, and HDTV, and the internet, and at our photo processing labs, etc. CRTs were 2.2, more or less, and which may be gone now, but LCD monitors have a necessary standard chip to remove the standard 2.2 gamma always found in our images. Why fight it? :)

"Measuring" something different probably reflects an error in the measurement process. How do your images actually look? (when monitor is calibrated). Gamma is brightness, and LCD monitors are notoriously way too bright by default, so 2.43 might be imaginable, but calibrate it first.

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It will depend on your intended use of the image.

If you intend to print it, or display it on other monitors that you know to be calibrated to a standard, you should definitely use the standard 2.2 gamma so that what you see matches closest to the final result. A fully color calibrated workflow would be even better, beyond just gamma.

If your image is to be shared to other uncalibrated monitors, i.e. the web, you have a little more leeway. The sRGB standard was developed to represent the average monitor in use at the time, and it adheres closely to a gamma of 2.2. Note that while the sRGB formula uses an exponent of 2.4, it uses some math tricks to line the curve up with a simple 2.2 gamma - don't get confused by this. I'm not aware of any surveys to see how well a typical modern monitor matches sRGB, and it's possible that your monitor is closer to average than the standard is, so leaving it at its native gamma could be acceptable.

  • thank you for your feed-back. Indeed the final goal is to use the monitor to create/view a future printed material or display the content on other sRGB calibrated monitors; But here we go again, according to Pinhollow Euri answer (make sense), creating 1D LUT for video card (8bit to 8bit), forcing the display to use 2.2 instead of native gamma value, will only cut the colour depth. In these conditions, which settings will be the best to use? – user124853 Mar 16 '16 at 19:48
  • @user124853 you need to judge for yourself whether more accurate color rendition will be worth the tradeoff of lower color depth. My off-the-cuff answer is yes, but I've never done a rigorous comparison. – Mark Ransom Mar 16 '16 at 20:46
  • "you should definitely use the standard 2.2 gamma so that what you see matches closest to the final result. " - downvote because make zero difference in colour managed output. – Euri Pinhollow Mar 20 '16 at 10:59
  • @PinhollowEuri what do you think color managed output uses for a gamma standard? – Mark Ransom Mar 20 '16 at 18:43
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    @mark-ransom: there is no abstract gamma standard in colour management strictly conforming to which is obligatory for getting accurate colour. ICC profiles may have several sets of point curves which specify device behavior, like this one. Read more in my answer and in chat. – Euri Pinhollow Mar 20 '16 at 19:12

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