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Hello,
I want the color coordinates for specific colors, iam using the Eizo EX3 which is just a spyder 5. I calibrated my displays and it was very easy and especially on my old TN the colors are way better, thanks for the great and easy tools! For interactive calibration of the white point, there are CIE XYZ values printed. I would like to see this coordinates after calibration for another color. I thought I could use this interactive whitepoint calibration window and just put the EX3 on the color I want to measure, but in the FAQ is written that at this point the calibration profile is disabled.
Is there any option / tool which just prints me which color is currently visible by EX3 and is using the calibration?
Thanks for your time!
Hi,
I want the color coordinates for specific colors
For what purpose?
Is there any option / tool which just prints me which color is currently visible by EX3 and is using the calibration?
You’ll likely want to use the “Untethered” virtual display.
Hi,
i’m writing my bachelor thesis and part of it is a color experiment. I examine three colors to each other, these should be accurate to one Euclidean distance. The laptop I use for pre-experiments seems to have a very bad color rendering and with calibration the experiment doesnt work. I would like to check the coordinates to do some math and say “This should work, the displayed colors are within the tolerance.” Or “Cant work because not in Tolerance”. If not in tolerance, I can change the colors to get 3 colors which have the specific attributes. For the experiment the colors themselves are unimportant only the relations to each other and for this I need the coordinates (inclusive Y/L* btw would be perfect). Iam asking here, because the interactive whitepoint calibration shows this values and is already really close to what I need, maybe there is a small workaround to enable usage of calibration profile during this step.
1. For untethered virtual display I cant find an entry, do you mean “Untethered” measurement? 2. Settings “MyCalibration”, Display “Untethered”, Auto Correction, Profiling open any test chart ignoring rgb, just put ex3, which is connected to the same pc, on colors I want to measure and get the L*a*b* ? If this values are correct, they are looking really out of position, which would explain a lot. Seems like I calculated RGB with wrong luminance.
Thank you!
i’m writing my bachelor thesis and part of it is a color experiment. I examine three colors to each other, these should be accurate to one Euclidean distance.
Euclidean distances are only really meaningful in a perceptually uniform colorspace (e.g. CIE L*a*b*, although that is not perfectly uniform – IPT may be a better choice, or DIN99).
For untethered virtual display I cant find an entry
Under “Display”, select “Untethered”. You’ll likely want to create a custom testchart with the colors you want to measure.
The original experiment is done in CIE Luv and the provided chroma coordinates u’ v’. Because it worked there, I didn’t think about another color space. Thank you for your remarks.
For XYZ <-> RGB Transformation I need RGB colorants, the measured L*a*b* values differs so I think I used the wrong. Do I need display specific colorants and can I get them from DisplayCal – there are various matrix / colorants in information?
Example: 203 203 203 entered in paint, which is in L*a*b* just 81.6 0 0 (RGB Model sRGB, Gamma sRGB = calibrated). b* is out of position, L* looks ok and a*=- 0.22 looks ok but b* = -13.28. For every grey b is -12 to -15 but should be 0. Wrong calculations or wrong calibration?
If you use a different reference white, make sure to specify that in you conversions from and to L*a*b*.
A differenz white would change just a little bit but not that much. This L*a*b* coordinates printed in untethered makes no sense for me. Another example, on a calibrated display the L*a*b* values tells for RGB(218, 198, 164) that its grey 75.0000 0 0. This values aren’t usable like that, so what are these values printed there?
A differenz white would change just a little bit but not that much
On the contrary. For XYZ -> Lab conversion, you need to specify a reference white. Only in this way will white have a* = b* = 0.
on a calibrated display the L*a*b* values tells for RGB(218, 198, 164) that its grey 75.0000 0 0
It means that the given RGB values measure the exact same hue and chromaticity (= achromatic) as white, which is expected when measuring a calibrated display.
This L*a*b* containing D50 correct? Because if I show 203, 203, 203 take the untethered L*a*b* as D50 -> XYZ -> L*a*b* 6700(profile tells me this is the display whitepoint) its just +/- 1 which is matching.
Shouldn’t the testchart, preconditioning profile, define the whitepoint?This L*a*b* containing D50 correct?
Sorry, I don’t understand the question.
if I show 203, 203, 203 take the untethered L*a*b* as D50 -> XYZ -> L*a*b*
What reference white are you using for the XYZ -> L*a*b* conversion (last step)?
Shouldn’t the testchart, preconditioning profile, define the whitepoint?
No. The reference white is the actual measured white (usually the first patch).
L*a*b* including always a reference white, like you said RGB values tells more yellow (b* negtive and -100 blue, +100 yellow) is needed for grey, so the reference white is more bluish like D50.
For the last step iam using the Media illuminated white point from my calibration profile which is 6700K or x=0.3095, y=0.3269 D65 would be even close (0.312713872, 0.329033956).
For the last step iam using the Media illuminated white point from my calibration profile which is 6700K
That will only work as long as it happens to match the actual measured white (probably reasonable to assume if the profile is from the same display and isn’t too old). I still don’t understand the rationale behind the exercise of going L*a*b* -> XYZ -> L*ab* though. The L*a*b* values you see on (e.g.) the “Untethered” window are already adapted. Assuming D50 for conversion of those L*a*b* values back to XYZ will not give correct results unless the display whitepoint is also D50 (which in your case it clearly isn’t). It would probably help if you showed the math you’re using. And if you really don’t care about the L*a*b* values and want the XYZ instead, you could get those from the measurement file (*.ti3).
1) Math:
For quick math iam using: http://www.brucelindbloom.com/ColorCalculator.html which are the same as “Colorimetry by Janos Schanda”
I implemented every Luv, Lab, XYZ, xyZ transformation, if Iam checking with 6700 iam using my calculation because I cant enter it there.2) Measurement adapting white point.
Iam pretty sure this values aren’t adapted after first white measurement, at least in my case. If so I could change the measured values, just because iam measure another white? Maybe important for this, I don’t finish the complete testchart.Ok in detail.
The profile is 2 days old, D65 sRGB XYZLUT+MTX, profile shows 6700 as white point, measurement exactly at the same spot.
The current profile is activated with profile loader + settings.
Display -> untethered
Testchart as is, shows the profile name.
Press Profile onlyTry 1:
measure white 255, 255, 255 on 6700 whitepoint display 90 -2.5 -16.5
measuring custom color (ignoring the test chart just created this in paint.net) 203, 203, 203 L*a*b* = 75 -2.5 -12.8
Exit Untethered measurementTry 2:
measure “white”, ignoring test chart and provide a complete different color, (0, 0, 255) on 6700 whitepoint display
measuring custom color (203, 203, 203) 75 -2.5 -13.5 (this small difference is on my display ok)
