Firmware bug: Gamma 2.2 doesn't apply calibration on monitor startup/mode switch

When gamma is set to 2.2 in the monitor settings, the monitor doesn’t seem to be using a proper calibration, after turning it on or switching video modes, unless you manually select another gamma level and go back to 2.2. The default white point at 100% is more yellow, and looking at the low blacks on Black level - Lagom LCD test I can see some are more red and others more green.

This seems to happen on both sRGB and DCI-P3, and I’ve tried DisplayPort and HDMI.

Here’s how to reproduce:

  1. Set monitor color temp to 6500k. Set gamma to 2.2. Set color to DCI-P3.
  2. Turn monitor off, then back on again.
  3. Open a window with a white screen or the lagom test pattern linked above. Open the OSD and set the gamma to something other than 2.2 then back to 2.2.

Results:
The colors change. The new colors are more properly calibrated compared to the old ones.

This proper calibration resets when the monitor is turned off, like in step 2, or when the computer changes video modes, or when toggling between DCI-P3 and sRGB.

Setting gamma to anything else like 2.4 does properly set the calibration when the monitor is turned on. Changing the gamma back and forth has no effect in that case.

My theory: With gamma 2.2 being the default, the firmware initialization code skips setting the built-in calibration when gamma is 2.2 because, the code writer assumes, it would already be that. However, the power-on state and built-in calibration for gamma 2.2 differ, with the calibration being superior.

Fix: Make gamma 2.2 initialize everything just like all the other settings do.

edit Also, this occurs on both firmware 1.05 and 1.06.

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Hi @Osoromnibus,

This is an interesting find. I will bring this to the team!

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Hi @Osoromnibus,

I have brought this to the attention of our firmware team. I will see if I can get any more updates.

What is the original firmware version of your Spectrum?

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My original firmware was 1.05, so I don’t know if 1.04 or below had the problem.

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Hi @Osoromnibus,

Thank you for confirming. Base firmware version was the detail our firmware team wanted to find out. I will let you know once there is more information.

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I can confirm this issue exists in both 105 and 106. My original firmware also was 105.
When turning the Spectrum on with gamma 2.2 configured, the white point is always yellowish.