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I purchased an ASUS PA329Q monitor to replace an NEC LCD2490WUXi2. I set up both monitors side-by-side and calibrated them to the same parameters (sRGB, D65, 150nit, gamma 2.2) using an X-Rite i1Display Pro and ProArt Calibration v1.07 for the ASUS and SpectraView v1.1.34 for the NEC. The colors displayed by Lightroom do not match -- not even close. Since I've successfully soft-proofed prints with the NEC for years, I trust its color accuracy. After much experimentation I've determined that ASUS ProArt Calibration does not generate or update an ICC profile, as do SpectraView and X-Rite i1Profiler. Without an accurate ICC monitor profile, how can color-managed applications such as Lightroom or Photoshop possibly render the proper colors?

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The color output must be normalized to be true.

This can happen in two different ways:

  1. On the computer through the software.
  2. On the screen by the hardware.

Higher-end screens often have a LUT (Look-up Table) that can be changed. This will do the color correction in the screen itself.

The monitor details say that it is"factory pre-calibrated for outstanding color accuracy" and the specification states that it has the ability to use a 14-bit LUT.

Lightroom can send uncorrected Adobe RGB and the monitor corrects it. Additionally, Lightroom and the monitor must both be using the same mode (Adobe RGB, SRGB etc.) or the wrong LUT will be applied.

  • Yes, but my understanding is that LR/PS/whatever don't have ARGB/sRGB modes. They convert image data to a Profile Connection Space (either XYZ or LAB) which defines an exact color, then use the monitor's ICC profile to convert this to the RGB values to send to the monitor. In the case of ProArt, the monitor's ICS profile is the stock profile installed with the driver. At best, this would need to cover the widest gamut of the monitor, so when using a narrower gamut such as sRGB, color resolution would be lost. – keg415 Jan 22 '18 at 1:31
  • In any case, it doesn't explain the color mismatch after ProArt calibration. I've been able to get a good match by calibrating the ASUS Darkroom profile using i1Profiler. But this is kludgy/impractical because I need to crank up red gain to 100, at which point LR looks good, but everything not using the profile is pink. I'm waiting for a response from ASUS. – keg415 Jan 22 '18 at 1:49
  • Interesting enough it does. The MOnitors ICC profile will be a static ARGB etc. profile that never gets updated - while the in monitor ICC is responsible for correcting. And no, they do not work like you assume. And if you are in the wrong mode, then you get a profile mismatc between monitor and color profile. – TomTom Jan 22 '18 at 7:40
  • So how do they (LR/PS) work then, if not as I described? What other means do they have for determining the monitor gamut other than the ICC profile? What is LR using to mark out-of-gamut monitor colors when soft proofing? – keg415 Jan 24 '18 at 16:49

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