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Hello!
I want to match the temperature of my surface book screen to a
set of lights in my studio (I paint from reference photos on the
screen.) So what I used to do is just match the screen to the
lights using the visual white point editor and then
calibrate/profile. That kind of works, but the calibration
curves for green and blue get pulled down a lot, which results in
some unwanted artefacts I believe, like color variations showing
up in a gray scale, and in difficulty to achive the desired color
temperature. I can’t change the color temperature of the LEDs
themselves, unfortunately. See first image.So I stumbled across these ‘LEE filters’ used by photographers.
One of them is supposed to convert a 6500K light to 4300K (filter
422). So I figured I’d try to fix one of these filters to my
screen, like a screen protector. That should change the color
temperature of the LEDs and make it easier to achieve the desired
temperature while staying closer to the native working paramters
of the screen in the calibration. (The color temperature of my
lights is about 4000K).Yes it seems to work well, the calibration curves look much nicer
(second image). All DE’s are also between 0 and 1 so.. Only
still, there still is a red bar in the measurment report
“Measured vs. assumed target whitepoint ΔE*00”. Does this mean
the color temperature is still not achieved? Or should I look at
the second line “Measured vs. display profile whitepoint”? The
red bar is bigger in the measurement report made with the screen
filter than without the filter on the screen. I’d expect this to
be the other way around…I attached the 2 measurement reports, without and with filter
attached to the screen.Thnx !
Hello!
I want to match the temperature of my surface book screen to a
set of lights in my studio (I paint from reference photos on the
screen.) So what I used to do is just match the screen to the
lights using the visual white point editor and then
calibrate/profile. That kind of works, but the calibration
curves for green and blue get pulled down a lot, which results in
some unwanted artefacts I believe, like color variations showing
up in a gray scale, and in difficulty to achive the desired color
temperature. I can’t change the color temperature of the LEDs
themselves, unfortunately. See first image.Calibration banding/posterization can be caused by GPU limitations (bitdepth in luts without dithering) or by color management rounding errors.
Simulating an idealized version of your display (1 TRC curve, matrix, synthetic profile) with DWMLUT and using that idealized profile as display profile should minimize these issues.
-create a synth profile with same WP & primaries and your most common TRC (2.2, sRGB, wahetever)
-create a LUT3D (.cube), source that synth porfile, destination your custom made ICC profile with DisplayCAL
-load LUT3D in LeDoge DWMLUT (https://github.com/lauralex/dwm_lut)
-set as default display profile on OS the synthetic profile (change DIsplayCAL preset to current for validations)(if you had an AMD card it would be easier, just create a new calibration with a single curve matrix profile, if your display is well behaved, but DWMLUT trick works on any hardware, it’s like having a display with HW internal calibration).
“Measured vs. assumed target whitepoint ΔE*00”. Does this mean
the color temperature is still not achieved? Or should I look at
the second line “Measured vs. display profile whitepoint”?This is distance to daylight curve of whites because we usually aim to whites in taht curve: D65, D50, D55, D58…. Thet dE error is a hint of green-pink tint compared to those whites.
If you are using a visually matched white to another source ignore it.
