Displays Display Calibration - How Good a Match Can You Get?

Apparently - and yes, this is research I should have done before bidding on that Huey - a colorimeter with exposed filters, like the Pantone Huey, can start to fail in as little as a year or two; sealed units with the filters behind glass, like the Colormunki Display I just bought, are good for a lot longer (but do still degrade.)

You're welcome to borrow this Colormunki, if you cover insured postage both ways and don't do something daft like try to calibrate your nostrils or eat your dinner off the lens.

 

This thing's *fun* - and tells me that the manufacturer overshot its estimation of the display's contrast ratio (surprise, surprise - the bumph claims 1,000:1, DisplayCAL measures 839:1.)

Code:

14:42:50,712 Setting up the instrument
14:42:50,712 Product Name:      Colormunki Display
14:42:50,713 Serial Number:     CM-19.B-02
14:42:50,713 Firmware Version:  v2.28
14:42:50,713 Firmware Date:     29Jan14
14:42:50,713 dispcal: Warning - new_dispwin: Expected VideoLUT depth 11 doesn't match       ↲
             ↳ actual 10
14:42:50,713 Current calibration response:
14:42:50,713 Black level = 0.1398 cd/m^2
14:42:50,713 50%   level = 25.43 cd/m^2
14:42:50,713 White level = 117.37 cd/m^2
14:42:50,713 Aprox. gamma = 2.21
14:42:50,713 Contrast ratio = 839:1
14:42:50,713 White chromaticity coordinates 0.3123, 0.3288
14:42:50,713 White    Correlated Color Temperature = 6527K, DE 2K to locus =  4.8
14:42:50,713 White Correlated Daylight Temperature = 6529K, DE 2K to locus =  0.1
14:42:50,713 White        Visual Color Temperature = 6355K, DE 2K to locus =  4.6
14:42:50,713 White     Visual Daylight Temperature = 6526K, DE 2K to locus =  0.1

 

Yeah, to be fair it might have been 1,000:1 eight years ago...

 

I really should be doing other stuff, but I figured I'd see what difference the calibration makes.

Here's the uncalibrated monitor, as compared to sRGB:



And here's the same monitor, same display settings, but with the calibration file applied:



Things look a little washed out to my eyes, maybe, but I guess it'll take some time to adjust to colours being right instead of how they were before.

 

Here you can literally see the colours being pulled closer to where they're supposed to be.

Uncalibrated:


Calibrated:


Should have bought one of these things *ages* ago!

 

Playing some more (YES I HAVE DEADLINES TO HIT SHUT UP SHUT UP SHUT UUUUUUUUUUP!)

Found an option to compensate for ambient lighting and actual environmental colour temperature as measured by the colorimeter (which, it reckons, is around 6,000K rather than 6,500K - guess my 'daylight' bulbs aren't quite up to snuff), and realised I'm probably using the gamma curve setting wrong (setting it to sRGB because that's what I want, instead of setting it to 2.2 'cos that's what the monitor reckons it's set at.)

Eyeballing it, the result is that some of the colours that were washed-out on the original colour profile are a bit deeper now, though still paler than turning colour management off altogether. It has, however, brought the maximum delta-E even further down:



And pushed those colours at the bottom of the gamut chart a bit closer to their targets (though they're still not quite there yet, and probably never will be on this monitor.)



Pretty good match to the gamma curve, though it loses it at 85-90 percent:



And the RGB gray balance is fine down to about 15 percent, after which it goes all skwiffy - thanks, I'm guessing, to the TN panel.



Considering each calibration takes about 20 minutes (which is a lot faster than a Spyder - apparently they take about an hour to do the same thing!) I should probably leave it there. Still, fun!

 

The thought had occurred!

 

Things I has learnded throughout this process:

• Don't buy old colorimeters, they don't work.
• Does your monitor have a special sRGB mode that actually works, unlike mine which is massively too warm? Then set the gamma curve in DisplayCAL to sRGB.
• Does your monitor not have a special sRGB mode that actually works? Then set the gamma curve in DisplayCAL to 2.2. Don't try to get smart, it's the default for a reason.
• Don't set the curve to "As Measured" unless you want the colour correction to only apply to images in colour-managed applications; you need a 1D LUT to correct non-managed stuff, like the desktop environment, and that only gets generated if you pick a curve.
• Is your job video production? Congratulations, you're going to need to piss-arse about with the 3D LUTs. Is your job not video production? Leave it alone, only madness awaits you there.
• If your colorimeter has a way to measure ambient lighting, use it. Also, use DisplayCAL's handy-dandy interactive adjustment screen to match the brightnesses between your displays for best results (paying attention to the numerical figure, not the "hit the bar in the middle" arrows.)
• Firefox needs you to go into about:config and set gfx.color_management.mode to 1, otherwise it'll only apply your colour correction profile to tagged images which will leave you spending half an hour trying to work out why the heck the pictures look different in the browser than in your image editor like an idiot YES I'M TALKING ABOUT MYSELF.
• While you're in there, set gfx.color_management.enablev4 in order to take advantage of additional information in DisplayCAL's ICM profiles. Though don't bother putting the location of the ICM file in gfx.color_management.display_profile 'cos if you leave it blank it'll automatically use whatever profile you've got set in your display settings.
• Got a wide gamut display? This is all probably going to be a massive pain in the arris. Serves you right, you flash get.

 

And knowing what I now know, I've had another crack at the laptop:



Happy with those figures.



Closer adherence to the sRGB gamma curve than my desktop.



Much better grey balance at lower intensity.



Pretty good gamut coverage, too - 95.5 percent.

 

Ooh! Ohh! Another thing I has learnded: when the instructions say "let your display warm up for at least half an hour first," let your display warm up for at least half an hour first. Seriously. I've got a test pattern image that does the checkered-boxes-next-to-grey trick to tell you your display's gamma: right now, having just turned it on, it's at a 1.7; in half an hour's time, it'll be at 2.2 without me doing jack.

 

I don't know of any publishing software which supports 3D LUTs. (I'm not saying it doesn't exist, I'm just saying I don't know of any - but then I'm sat here using a combination of The Gimp, Google Docs, and LibreOffice to do all my work, so I'm not exactly in-the-know when it comes to expensive proprietary stuff.)

They are, however, used heavily in the film industry: