Thread: [howto] adjust screen color profile
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Kallela is offline Kallela
2013-04-02 , 10:17
Posts: 49 | Thanked: 93 times | Joined on Jan 2012 @ Finland
#47
The two display entries (c1 and fe) in mce.ini correspond to two different display panel versions from two different manufacturers. That is why different N9s may have different color reproduction. You can dig up your panel version information for example from boot log with dmesg and grep:

Code:
dmesg | grep -i pyrenees
("Pyrenees" is the code name of N9 display panel, regardless of the manufacturer, I guess.)

Here is my outcome:

Code:
[    0.307434] panel-nokia-dsi display0: pyrenees panel revision c1.8b.96
[   11.115112] atmel_mxt 2-004b: firmware: requesting RM-696_Pyrenees_LGD_V1_1.bin
Panel revisions (and my observations):
  • "c1" (by LGD, LG Display)
    • reddish tint sometimes
    • more visible pixel matrix
  • "fe" (by SMD, Samsung Mobile Display)
    • greenish tint from extreme viewing angles
    • less visible pixel matrix

Originally Posted by mcbook View Post
A set of values for a profile looks like this

- 3 values for brightness (lower limit, upper limit, high brightness -> I wouldn't touch those numbers as I don't know what they are doing)
-3 values for the red color channel (R;G;B)
-3 values for the green color channel (R;G;B)
-3 values for the blue color channel (R;G;B)

...

e.g
Neutral=0;330;0;175;48;13;22;206;28;8;8;240;330;9900;0;175;48;13;22;206;28;8;8;240
The brightness values are the ambient brightness levels, measured by the ambient light sensor, not the display brightness! Unfortunately, I don't know either what that high brightness mode is, so there is still something to figure out. Maybe that is related to the selected display brightness level?

So you can define different color tunings for different lightning conditions inside one color profile (for day, night, etc.).

For example in that Neutral color profile, there are different color tunings for ambient lighting range 0-333 (i.e. 0-100 lux) and 333-9900 (i.e. 100-3000 lux), respectively. You can add more ranges, if needed. (Actually Neutral profile is not fully defined, as the range from 9900-(-1) (i.e. from 3000 lux to infinite) is not covered!)
 

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