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Following the instruction given in this question, I calibrated my monitor meticulously so that it adopts the standard gamma correction across all platforms, e.g. Internet, Photography, etc.

Now what is the standard value of Gamma that I should set? If no standard is given, at least the widely used value that meets the demands of Photography. How about the monitor's setting? should I reset it to "Factory settings"? Or manually reset its RGB value and if yes, what are the ideal values?

  • All this is wasted effort if standard, stable (consistent) viewing conditions are not in force in harmony with equipment settings. Human perception is directly involved in colour management. – Stan Jun 2 at 18:06
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Physical DISPLAYS for Rec709 are defined as a gamma of 2.4. Note that this is different than the reciprocal gamma that the signal is encoded with. The sRGB spec may indicate ~2.2, but there's more to the story.

sRGB has a signal gamma (i.e. the stored image gamma) of ~1/2.2, though it is more precisely set as:

enter image description here

If this is fed into a monitor with a gamma of 2.4, for a total system gamma gain of 1.1. Why is this often the case? For sRGB per the IEC standard, the monitor's luminance is speced at 80 cd/m2. That was way back when, when CRT monitors had a hard time displaying brighter. Today LCD monitors can easily be set to 200 cd/m2 or more, and phones are available as high as 1200 d/m2 !

If you set your monitor brighter you are almost certainly going to set the monitor's gamma higher as well. Studies have shown that typical users have their monitors set over 160 cd/m2, and gamma much higher than 2.2 to 2.4 - one survey found that over 50% of users had the gamma at 2.5 and HIGHER!

The transfer curve of the sRGB signal is "close to" a 2.2 gamma, but it is actually a piecewise curve, that is actually a higher gamma at the top end of the video range and a lower gamma at the bottom of the video range.

Part of the issue is that ambient lighting has a very substantial effect on the perception of the colors and lightness of your monitor.

If you are in a bright environment with a dark monitor (peak white at 80 cd/m2 or lower), then you'll want your display gamma lower (i.e. 2.2) as that will brighten the image to compensate for the ambient, but unfortunately also reduce contrast.

If you increase the monitor's peak white level (say to 200cd/m2), you'll also want the gamma higher like 2.4 which will darken the midrange and increase contrast, which is needed due to the higher ambient lighting "washing out" the blacks.

Related: The eye's response to light is also non-linear — and that non-linearity is not the same throughout the visual range (i.e. even our non-linearity is non-linear!) and depends on total brightness.


For sRGB per the IEC standard, 80 cd/m2(includes veiling glare), gamma approx ~2.2, with an ambient of 64 lux (encode) or 200 lux (typical).

For sRGB per the SMPTE standard, 120 cd/m2.

For Rec709's BT1886 (monitor) and BT.2035 (viewing environment) the monitor gamma is 2.4, the whitepoint luminance is 100 cd/m2 and the ambient is 10 LUX (dark!)

And see this PDF for more.


What Gamma?

So, how should you set your gamma? It depends on what you are doing, your environment, and if your monitor has an internal LUT (like a high end NEC or Eizo).

If you are using color management, then setting the monitor to a NATIVE gamma (i.e. relying on it's internal LUT), and profiling it with an XRite i1 Display Pro leads to good results.

That said, I usually have my NEC PA271W with a 14 bit internal LUT set to an L* curve.

And my Samsung 245t monitors needs hardware (front panel control) tweaking to get their "native" values in line with reality for a reasonably flat profile relative to sRGB.

In other words, your mileage may vary, along with your ambient conditions. But if you are using ICC profiles and color management, I find best results by making profiles, looking at the profile's curves, and adjusting the hardware controls on the monitor, profiling again, until the profile curves are relatively smooth.

The reason and theory is that you want the ICC profile to do as little transforming as possible.

(Edited for clarity, minor corrections, and to add a few other ideas.)

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Gamma and RGB values in your monitor's setting are subjective - they only apply to your monitor.

The only way to calibrate a monitor correctly is using a device such as a Huey Pro. This way the COMPUTER knows exactly what the MONITOR is putting out and can correct accordingly.

I set gamma to 2.2, then calibrate.

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    This is not correct, you usually have an encoding gamma correction done at the image capture and a decoding correction done by the display itself. For instance BT.709 OECF (± 0.5 gamma) which encodes HD camera linear light values to non linear R'G'B' components and your display that for example use sRGB (2.2 gamma) or BT.1886 EOCF (2.4 gamma) and decodes those non linear R'G'B' components. – Kel Solaar Mar 23 '16 at 8:04
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Within the Windows universe, the standard gamma value is 2.2. With Mac OS X 10.6 and later it is also 2.2. Prior to that Macintosh computers used either 0.55 or 1.8. It should be noted that JPEG images carry gamma-encoded values (the intensities are not linear).

  • NTSC also used gamma 2.2 (as per ISBN 978-0-12-391926-7, page 320). – U. Windl Jun 3 at 22:59
  • NTSC used a 1/2.2 encoding gamma, but TV sets were more typically 2.4 — this is similarly true of Rec709, which specifies a signal gamma of approx 1/2.0 but the BT1886 monitor spec uses a display gamma of 2.4, in both cases resulting in a system gamma gain, intended to display in a darkened living room. – Myndex Jun 21 at 22:40
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There are different standards.

sRGB which is the typical colour space of computer monitors refer to gamma 2.2, and is most commonly used in JPEGs as PC screens are assumed to be where it ends up.

BT.709 used in HD TVs are gamma 2.4.

I tend to find those gammas to be too pale so I like to use 1.8. But in a PC monitor/ Photography context, standard is 2.2.

  • BT.709 doesn't actually define a display gamma (EOCF / EOTF) but an encoding gamma for HD cameras (OECF / OETF). The EOCF standardised for HD TV is BT.1886. – Kel Solaar Mar 23 '16 at 7:58
  • The CIE L* uses a gamma of 2.38 (1/0.42) as per ISBN 978-0-12-391926-7, page 261. But as noted if encoding is "incorrect", decoding has to compensate for it. – U. Windl Jun 3 at 23:07
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because there is no defined standard for gamma across all platforms, i tend to take an average and set it to 2.0. this works pretty well moving colour between pc and mac.

  • There is a defined gamma, and it is sRGB. MacOS has been sRGB/2.2 since 10.6, circa 2008 – Myndex Jun 1 at 18:34

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