Why don't two calibrated monitors agree?

[Frank Petronio]

I use two NEC P221W monitors and a Spyder3Elite calibrator. I set both monitors to identical brightness, color temp, contrast, etc. and run the calibration routine. I use an 18% grey desktop background.

When I get all done, my Left Monitor is pinker and the Right Monitor is greener. Subtly, we're talking 2 points difference on the Photoshop Hue Saturation slider. But annoying.

I understand that my calibrator is software only and not tied to my hardware, it isn't like the fancy ones that give feedback to the monitor to produce a perfect neutral. But nevertheless - and maybe I'm having a brain fart or senior moment here - if I adjust my images to taste on one monitor, it will be different on the other. Doesn't this mean all this effort to calibrate is for naught and just a ballpark guesstimate, with at least a few points of fudge?

Or am I just in need of reeducation, some time spent working out in the Adobe fields where I can learn to become a proper digital citizen and go along with the prevailing dominant workflow?

[C. D. Keth]

Did both monitors get at least an half hour to warm up before your calibration and are you giving them at least an half hour to warm up before using them for color decisions?

[Frank Petronio]

of course

[C. D. Keth]

of course

Had to ask. Do both monitors have roughly similar numbers of hours on them?

[Amedeus]

What is the videocard you are using ? Spyder3Elite calibrator is fabricating calibration constants the driver routines are using to fudge the output. There are limits on how effective this is, all determined by the video circuitry but more importantly by the monitor. THe NEC you are using I believe has 6 bit LCD panels. This makes for 64 levels/color to be displayed. It only takes one level per color difference for the eye to see the difference on two monitors side by side.

Another source of mismatch is the aging of the backlight. CFL backlights have issues but so do LED backlights. The latter has typical binning issues that yields minor color differences. You won't notice on a single monitor but as soon as you put two side by side ... bingo.

If absolute color calibration is a must, then use LCD monitors with 10 bit panels and buy them from the same batch if possible to ensure best possible aging and binning of the backlight LED's. It should be said that 10 bit LCD panels give you much more room for proper calibration.

[Frank Petronio]

Thanks. These are the cheapest halfway decent monitors but no match for Eizos or anything good. I'm not really expecting a perfect solution, I know just to use one monitor consistently and use the other for tools, but I wanted to get an idea why it was happening and Rudi's explanation makes a lot of sense.

(Yes I bought them within two weeks of each other but they probably aren't from the same batch. And I am not using any sort of quality video card. Here is a long thread on my bargain system: http://www.largeformatphotography.info/forum/showthread.php?83585-Mac-Mini-Server-QuadCore-Use-as-a-Desktop&p=856818&viewfull=1#post856818)

[Amedeus]

Looks like you have a fun system set-up with the Mac Mini Server. Many years ago I used a regular (slow) Mac Mini for PS2 for the longest time and yes, I calibrated my monitor with Spyder to match my printer. I still do the same on my 27" iMac and my laptop. The video card is not the bottleneck here, it's the monitor.

[Frank Petronio]

Well the onboard Intel video on the Mac Mini is what keeps it from being a great system... if Apple put a real video card (even on par with the laptops) then the Mini might cannibalize other sales so I "get it" but it is so close otherwise!

For now it is OK but as people move to higher-resolution displays and create more work for Retina-type displays, I feel kind of funny working on a desktop that is lower resolution than my iPad... it is a weird period of transition ahead for a couple of years.

[Light Guru]

Thanks. These are the cheapest halfway decent monitors but no match for Eizos or anything good. I'm not really expecting a perfect solution, I know just to use one monitor consistently and use the other for tools, but I wanted to get an idea why it was happening and Rudi's explanation makes a lot of sense.

(Yes I bought them within two weeks of each other but they probably aren't from the same batch. And I am not using any sort of quality video card. Here is a long thread on my bargain system: http://www.largeformatphotography.info/forum/showthread.php?83585-Mac-Mini-Server-QuadCore-Use-as-a-Desktop&p=856818&viewfull=1#post856818)


Not being from the same batch could definitely contribute to the issue. However I'm suspecting that the issue is that you are using a Mac Mini.

Don't get me wrong Mac Minis are great little machines but the graphics card in them is simply not designed to run calibrated dual displays. The video out options on the mini do not allow for two monitors to be connected in the same way, you have one mini display port and one HDMI port. While there are some similarities in the connections they are still different connections.

Im not familiars with your particular monitors but I know that many monitors also have HDMI along with the standard DVI. With one of your displays connected via HDMI and one connected via DVI this could be the issue on the monitor itself. If the display handles those inputs slightly differently.

[timparkin]

Have you got any reporting on your calibration device? Most calibrations don't 'finish' with an accurate answer - they have a margin of error. If that margin of error is 1 point on the hue saturation slider (which is fairly accurate) then a 2 point difference would be possible. You might get a different result each time you calibrate the system too so it might make sense to try to calibrate the first one a few times, saving each profile, and choose the one that matches the best.

[William Whitaker]

My right eye is cooler than my left eye. True, my eyes have a lot of hours on them, but I first noticed this when I was a kid.

I know I sound flip, but seriously, if you're going to extreme measures to calibrate monitors, aren't your eyes part of the overall system?

[Frank Petronio]

All good reasons - I'm sure the anemic Mac Mini video has a lot to do with it.

The practical solution is to just use one consistently for editing, which is what I've done. It's just annoying.

[Bruce Watson]

I use two NEC P221W monitors and a Spyder3Elite calibrator. I set both monitors to identical brightness, color temp, contrast, etc. and run the calibration routine. I use an 18% grey desktop background.

When I get all done, my Left Monitor is pinker and the Right Monitor is greener. Subtly, we're talking 2 points difference on the Photoshop Hue Saturation slider. But annoying.

Decent mid-level monitors, but not top end at all. Given the quality level of the monitors in question, I can't imagine that you could do better. If you want better anyway, I think you'll have to buy monitors that actually are better. Sorry -- not what you wanted to hear.

[pherold]

Have you got any reporting on your calibration device? Most calibrations don't 'finish' with an accurate answer - they have a margin of error. If that margin of error is 1 point on the hue saturation slider (which is fairly accurate) then a 2 point difference would be possible. You might get a different result each time you calibrate the system too so it might make sense to try to calibrate the first one a few times, saving each profile, and choose the one that matches the best.

I think Tim's on the right track in finding a solution here. Our eyes are just so very good at discerning differences in color when viewing two things side by side. Frank, I'd like to see you try to match the whites of the monitors first. Pick one as your standard, and adjust the brightness & color of the other one so that a blank, white document comes out looking identical on both monitors. Then, go ahead and calibrate the second monitor as it is in this state. Generally, if you can get the whites looking the same, the rest of the color range will follow when you calibrate.

[Frank Petronio]

Thanks!

[Jim Andrada]

Hi Frank

I think you need two or three of the following

http://www.necdisplay.com/p/desktop-monitors/pa301w-bk-sv

Actually you can get the same display without the color gizmo for about $250 less and use our own color calibration HW.

[Doug Fisher]

I don't know if you are ever going to get a perfect match between two monitors but here are a few thoughts/questions - If you are not using the SpectraView software, your Spyder software is not able to take advantage of an NEC monitor's capability to receive an uploaded unique LUT set into each monitor itself (versus just loading one set into the display card's LUT), is it? If not, then your NEC's monitor's capabilities are not being fully exploited. Additionally, if you just have one video card and no SpectraView software, even if you calibrate both monitors your computer/video card will be applying just one profile, therefore, necessarily one of the monitors will be using a profile created for the other monitor, right? Finally, have you checked to make sure the Spyder 3 Elite is fully capable of meeting the extended capabilities required for a wide gamut NEC monitor (it may be, I don't know, but thought it was worth checking)?

Considering how much you have invested in two of these monitors, I would go ahead and invest in the NEC Spectraview II software. I have been working on trying to match two different monitors via SpectraView and NEC support confirmed the software is able to create unique profiles and load them into each monitor which means as long as you have Spectraview running you do not have to have two separate video cards to have two uniquely profiled monitors. The Spyder 3 is compatible with Spectraview II.

Just some thoughts to help you troubleshoot things.

Doug
---
www.BetterScanning.com

[Jim Andrada]

When I was at Siggraph I talked with the NEC display folks and they told me that a good unit like Spyder or Color Munki would be able to profile the display(s) as well as the gizmo that NEC sells. The rest would be up to the software.

I think some display cards do support multiple profiles but not 100% sure. I'll check on that. By the way, the guy at the NEC booth also recommended looking into a refurb unit which is a lot cheaper.

Full disclosure - NEC Tokyo is my main client although in the storage area, not displays

[Darin Boville]

Ah, I say screw calibration! Eyeball it to get it in the ballpark and then don't worry about it. :)

I tried calibration once. No matter what settings I adjusted I couldn't get the print to glow.

--Darin

[Greg Miller]

The calibration device only measure a small portion of the screen. And no monitors are 100% consistent across the entire screen. You could calibrate the same monitor twice and get slightly different results just by moving the measuring device a bit.

It might be interesting to calibrate one monitor, then copy the profile file so that it is also used for the 2nd monitor.

[Doug Fisher]

>>And no monitors are 100% consistent across the entire screen.<<

While true to a varying amount depending on the monitor model and manufacturer, you might be surprised at how little it varies with the better NEC/Eizo/etc. monitors that have the built in equalizing technology.

[patrickjames]

There are some good suggestions above.

I think you owe it to yourself to try other software. Two that are good, and have demos, are basiCColor (http://www.basiccolor.de/en/) and Coloreyes (http://www.integrated-color.com/cedpro/coloreyesdisplay.html). I haven't checked to see if they work with your puck but they probably do. You also may want to look at the free dispcalGUI/Argyle. When I bought a new MacMini a year ago I basically was left flappin' in the breeze with my Profilemaker and Eye One Match software by X-Rite. I didn't feel like paying them $600 to upgrade for just monitor support and there was no less expensive option for my Eye One Pro so I started to look around. I discovered dispcalGUI/Argyle and, although I found it to be a bit of a speed bump at first, it really does a thorough job. It is slow though, FYI. Real slow.

I am just throwing these out there as options.