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Wide Gamut Monitor Calibration Lessons Learned
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WARNING: This is probably more information that you ever wanted to know on display calibration instruments and custom color profiles for displays
So, I have spent the last few evenings attempting to get my new 27" iMac display calibrated to my satisfaction (cue the comments on how my standards are too high). I have learned a few interesting things in the experimentation and technical discussions with the folks at Integrated Color Corp.
1) The 2009 model LED backlight Apple displays have considerably wider color gamuts than the previous conventional CFL backlight displays.
2) The majority of this gamut extension is in the blue/purple region of the colorspace.
3) Many of the older generation colorimeters (the hockey-puck instruments used to measure luminance and chroma on monitors) have issues accurately measuring the spectra of the newer LCD displays. This usually shows up as significant errors in white balance/color temperature.
4) The new Datacolor Spyder3 series instruments are probably the most accurate wide gamut units commonly available right now. Unfortunately the previous champion in accuracy, the Xrite DTP-94 (which of course I own) is seriously hosed when it comes to measuring white point on my new 27" iMac. The cheapest way to get the Spyder3 hardware is Spyer3Express ($89 at Amazon). THe older Spyder2 instrumemnts are nowhere as accurate with wide-gamut devices as the new version 3 ones.
5) The software that comes with the Express version of the Spyder is so basic & limited that it is almost useless for serious work.
6) The two best software packages for display calibration (using 3rd party instruments like the Spyder) are Color Eyes Display Pro (CEDP) by Integrated Color and BasiCColor Display by some German outfit I forget the name of. I have owned and used CEDP for several years due to the huge range of options and the accuracy of the profiles it creates.
7) Even with an accurate color profile, certain hues of what used to be seen as blue on narrow-gamut displays will display with a purple cast on the wide-gamut devices. This is actually correct and no amount of calibration will remove it. It is caused by the older devices clipping the blue spectrum before it extends into areas of the colorspace that transitions into purple. Similar effects can happen when printing photos with the right shade of blue - as you go from the display to the narrow gamut printer, colors will get clipped and hues will change. The color profile process in the printing software will attempt to map the out of gamut colors to the closet in-gamut equivalent, but the blue/purple region is very tricky.
8) Currently, the most accurate calibration solution is the CEDP software with one of the Spyder3 instruments. Integrated Color sells a package for $299. THe BasiCColor SW is also quite good, but it is very difficult to actually purchase in the US.
9) If that's too rich for your blood, the Spyder3Pro package from Datacolor is the next best thing. I bought the Express because I was going to throw out the software anyway. The basic colorimeter is the same. This is about $160 on Amazon.
The out of the box profiles on the new Mac's aren't horrible. There is some gamma/gray scale issues and the white point is too cool (they run about 7000+ instead of the 6000-6500 range that is normal for color work. The color rendition is actually pretty close.
The link for the Color Eye Display Pro stuff is:
www.integrated-color.com
Originally posted at 10:57AM, 20 November 2009 PDT
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HD_Keith edited this topic 31 months ago.
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Wow, Keith - great post with a lot of info. This explains what you were seeing.
I lucked out and have the Spyder3 pro but I just use the SW that came with it. Based on what you know is there anything I should do different - other than purchase the Color Eye Display Pro? I'm not sure I want to spend that much on it, although I see they have a fully function trial that should run for 10 days with my Spyder3.
Posted 31 months ago.
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The software with the Pro is more fully featured than the Express. I tend to set my white point down about 6000-6200K instead of at D65. I think you get a better alignment to what you see on a print. I also think most folks are running the luminance way too high. I usually calibrate for 90-100 cd/m2.
I do not know if the Spyder3Pro SW uses the Lookup Table (LUT) in the graphics controller or just a software matrix. You can get better range of adjustment without inducing banding by accessing the LUT directly. CEDP does this. CEDP also can directly control the brightness of Apple monitors as well as hit luminance targets via the profile instead of just measuring the max luminance and requesting the user to adjust the display brightness manually. CEDP also can use DDC (Digital Data Channel) to directly drive internal monitor controls for luminance, chroma and grayscale on high-end monitors that support it such as some of the Ezio's and NEC's. CEDP also lets you place additional grayscale control points if you have problem regions in the neutrality of your grayscale after the default calibration.
Given how good the new 27" iMac display is, the Spyder3Pro software is likely good enough. Get a test image of a continuous gray scale (or a very fine grained step wedge) and look for uniformity and banding. The new iMacs, unlike my 24", have a good range of adjustment on the brightness control, so hitting a reasonable luminance is not a problem manually.
Fortunately, you have a good instrument. The only other device that is rumored to work well with wide-gamut LED monitors is the Xrite i1Display2 (about $250). That is the current evolution of the old Gretag-Macbeth instrument I also have.
So I'm curious - does the planet on the Star Trek scene on Apple's home page look a little purple to you too?
Posted 31 months ago.
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Thanks. Maybe I'll try the 2 week trial of CEDP to see if I can tell the difference in the calibration.
The planet is very slightly purple. But I wouldn't have noticed if you hadn't mentioned it.
Posted 31 months ago.
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You all are way too picky :)
Originally posted 31 months ago.
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kevin.krause44 (a group admin) edited this topic 31 months ago.
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Great Information!
Posted 31 months ago.
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There is an even better instrument, the Xrite i1Pro. The problem is I think the only way to get it now is as part of the i1Extreme (or some such stupid name) package which is their top of the line display, print and projector calibration kit. Somewhere in the neighborhood if $2500 I think :-(
Posted 31 months ago.
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On the other hand, $2500 seems like a small price for the best. And if you have one, you can loan it to us!
Posted 31 months ago.
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Dream on ... :-)
Posted 31 months ago.
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