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What is the Best Multi-Monitor Calibration Tool? 55

Posted by Cliff
from the lots-at-once dept.
sojourndeath asks: "I am looking for a good way to calibrate multiple monitors (30-40), so that their color looks similar? It seems like everything I find is for profiling your monitor to your printer and scanner. I need to be able to have a bunch of users see the same color on any monitor? Does anyone have a good, accurate way of doing this?"
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What is the Best Multi-Monitor Calibration Tool?

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  • by B4RSK (626870) on Sunday February 20, 2005 @06:52AM (#11727909)
    You're going to have to calibrate each monitor separately using the same calibrator.

    Repeat once a month or so.

    I don't envy you having to do this!
    • I haven't seen any posts that mention the GretagMacbeth EyeOne [i1color.com] units. They're very spiffy, and they come in cheap (monitor calibration) to expensive (match your printer setup with the color of your shoes). I have an EyeOne Display that I loan out to coworkers when I'm designing websites, since most LCDs are woeful at displaying accurate dark colors.
  • calibration (Score:4, Informative)

    by thaWhat (531916) on Sunday February 20, 2005 @07:13AM (#11727948)
    I hope that they're all the same brand, or as the previous post mentioned i dont envy you. Some brands (Barco for one) have *luxury* an auto-calibration tool for some of their monitors. From observation, it seems to take around 5 minutes per monitor. I hope this helps. otherwise L.E.D.s are sensitive to wavelengths similar to that at which they radiate. Perhaps if you obtain a multimeter and measure the voltage of each led for a given (standardised) setting for each monitor, at least you should have a sort of way to quantitatively compare the brightness/colour balance. Just a thought
    • Apple had high end "ColorSync" CRT monitors, just before the days of LCD. Their top end model had a calibtration button. Pressing it would cause the monitor to flash and buzz and flicker for a few minutes before finally settling down. Apparently it also had some sort of auto calibration like the Barco monitors.

      No, this wasn't a deguass cycle, they had that feature too, but degaussing only took maybe 25 seconds max
  • by jonadab (583620) on Sunday February 20, 2005 @07:29AM (#11727977) Homepage Journal
    > I need to be able to have a bunch of users see the same color on any monitor?

    If you wanted to have the _same_ user see the same color the same way on
    different monitors, that is theoretically achievable with good quality CRTs,
    assuming you can put them in identical settings and so on.

    But with different users, there is going to be a difference in perception.
    Some people see *significantly* more color depth than others, for instance.
    Also, some people's retinas are more sensitive to light than others, so they
    have most of their color resolution in the darker ranges; other people have
    eyes less sensitive to light and distinguish brighter colors better.

    I've discovered that most of my coworkers can't tell #305050 from #294D4A,
    even when they're side by side. To me, they're noticeably different in
    character, and if you show me one of them by itself, I know which of the
    two it is. (This is probably attributable more to the difference in
    blue/green balance than the slight variation in brightness, but anyway, I
    can tell.) One time I asked for a coworker's opinion on the brightness of
    a certain background, and she said it was too dark, so I grabbed the V
    slider (in Inkscape) and lightened it up a bit, then looked at her; she
    obviously didn't realize I'd changed it at all. So I dragged the slider
    over a bit more, and a bit more... after a bit I asked her how that was,
    and her response clearly indicated she still didn't see a difference. I'd
    changed it by probably 20 or 30 units per channel. (I quit asking for her
    opinion on colors after that.) She's an extreme case, obviously, but the
    basic phenomenon is universal: people don't all have the same eyes.
    • by Anonymous Coward

      I've discovered that most of my coworkers can't tell #305050 from #294D4A, even when they're side by side.

      You've got to be kidding. Are they perhaps blind? That's a brightness difference of 3 in the green channel (the channel to which humans are most sensitive).

      • BTW: there's an even a bigger difference in the red channel.

        They could have crappy monitors. OR the monitors aren't adjusted correctly. On mine 294d4a is darker and greener.

        Which brings us back to what the story is about. Even if the people can't _perceive_ the difference at he/she wants them to see the same things on their monitors.

        It's not such a dumb request. But I still don't see the point yet. Since if it's for a product, is that colour thing going to go all the way to the customer end? I suppose it
        • by Anonymous Coward
          I suppose he's building something like a multi-monitor wall or an art installation where multiple monitors form a single or repetitive image. In that case a monitor with different color reproduction would stick out like a bad pixel on a TFT screen.
      • > You've got to be kidding. Are they perhaps blind?

        That was my immediate reaction when I discovered this, but it appears to be
        fairly common.

        > That's a brightness difference of 3 in the green channel (the channel to
        > which humans are most sensitive).

        I don't think all humans are quite equally sensitive to the respective channels.

        The one coworker, who couldn't see a difference of less than about 30 on the
        V channel (using an HSV color model), even when watching it change, is
        abnormal, as far as I'm
    • by Anonymous Coward
      I've discovered that most of my coworkers can't tell #305050 from #294D4A,
      even when they're side by side.


      Uh, this depends on the monitor you're using as well.

      Most of the time people are just just lazy, they're not really paying attention to the differences because they don't care. Those colors look similar enough that most people just ignore the differences. That doesn't mean they can't see the difference, they just don't want to.
      • > Uh, this depends on the monitor you're using as well.

        It's a pretty decent quality nineteen-inch CRT, and I don't have any trouble
        seeing the colors on it.

        > most people just ignore the differences

        When I said they can't see it, I didn't mean that they didn't mention noticing
        a difference; I was pointing out how one object on the screen was a different
        color from the other, and they couldn't see it, not even when I put them side
        by side.

        I've also done a little checking within my family, and I'm pretty
        • Maybe you you are a tetrachromat. As in: A human with 4 distinct color receptors on his/her retina.
          Most humans are trichromats. Most (if not all) tetrachromats are females.

          Look here: TetraChromat [c2.com]

          ps. I had a very hard time telling those 2 colors apart, but could. I doubt I would have noticed if I
          hadnt known beforehand.
        • My parents can by [sic] handwaved because they're over 50
          I'm 50, and can easily tell the difference between the two colors (if one is painted directly on the other).
          In fact, if I look really closely, I can tell the difference between #305050 and #304E4C on my monitor.
          This may be partly due to brightness and contrast settings, but I think (like some others) that different monitors may display different characteristics.
    • This is one of those ambiguous uses of the English language.

      When I read it, I took it to mean,

      I want any given user out of a set of users to see the same colors on all monitors.

      It appears that you took it to mean,

      I want every user out of a set of users to see the same color on any single (or) on all monitors.

      Since the phosphers are fairly standard from monitor to monitor in the same manufacturing run (ie, red gives of a certian wavelength across a range of monitors) then it's easily possible
      • Obviously you don't know anything about applied color and calibration. Calibration is one of the biggest issues in any segment of the communication industry, most notably printing. Even the same monitor (CRT of course) can display color noticably different after warming up for an hour, and especially from day to day, week to week, and so on. If you're designing anything for print that involve a corporate logo, spot colors, or product matching, you have to calibrate your monitor *every single day*. And that
    • Different people really do have different amount of the red green and blue sensitive cones in their eyes, in fact, 1/1,000,000 has a mutation where they have 2x as many green receptors as any other color receptor. There's an exhibit at the Exploratorium where there's an orange dot that's really an orange wavelength of light, and then surrounding it there are differently proportioned red/green light mixes, and different people see that central orange dot to match WILDLY different surrounding mixed color dot
  • Pantone calibrator (Score:5, Informative)

    by whoda (569082) on Sunday February 20, 2005 @08:03AM (#11728036) Homepage
    Get a Pantone compatible monitor calibrator and software.
    Like this one [ephotozine.com].
  • It's called the old 'mark 1 eyeball'

    Can be used in situations such as correcting dented leading wing edges on fighter jets, and damaged theodolites, just to name a couple of the less important uses. :-)
  • by Andy_R (114137) on Sunday February 20, 2005 @08:41AM (#11728098) Homepage Journal
    Not all monitors have the same range of brightness/contrast and colour* gamut (range of colours they can display). If you do achiveve your stated goal, it will only be by making the best monitor you have display the brightness/contrast and gamut of the worst.

    Colour perception depends a lot on environmental conditions. On identical perfectly calibrated monitors, colours will not look the same if one is in a room with white walls and the other isn't... and the same goes for one being in a room with flourescent lighting, one being in the shade, one with a window behind it, or one being somewhere there is a pretty sunset happening outside the window.

    Users will disagree about the extent of variations caused by environmental conditions, and will disagree about colours. If you do calibrate with the best calibration tool on earth, users will simply not believe that you've done it right, and will resent their monitors being 'wrong' (ie different to the way they were before calibration).

    Monitors drift, especially cheap ones... as they warm up, as room temperature varies, and as they get old. Calibration is a neverending job.

    * I'm English, from England, and I know how to spell English words. It's not my fault the founding fathers didn't take a decent dictionary to America.
    • They did to Canada though... and those bloody Americans have been trying to subvert our perfect spellings! I mean, honestly, "color"... maybe in Spanish, but English, no...
    • * I'm English, from England, and I know how to spell English words. It's not my fault the founding fathers didn't take a decent dictionary to America.

      Interesting that you should say that, since Noah Webster was the person who did the most to reduce the illogical spelling which, like measles, chicken pox, typhus, typhoid fever, dysentery, scarlet fever, diphtheria, bubonic plague, and whooping cough, survived the journey from England. His dictionary of 1821 included the following:

      * musick became mus
      • Just to thow some more petrol on the fire.... ;)

        The poor yanks don't even know how to pronnounce the words they do have.

        For example, they pronnounce Lieutenant as "loo-ten-ant" instead of the proper "lef-ten-ant". After all what could be more obvious? ;)
      • Unless you think that "hour" rhymes with "whore," there is no logical reason for having a "u" in the word "color."

        Except colour is pronounced kol-ur rather than kol-or, at least where I grew up. And you seem to be implying that english is vaguely consistent - try the following on for size (it's a standard speech synthesiser nasty):

        Lawn mowers are thoroughly tough though.

        Cheers,
        Toby Haynes

        • kol-ur to mean Pepsi or Coke? I'd (Nat.Geog.) transcribe colo{u,}r as: kull-uh. So, to kill off this debate, colour should be spelt: culler.
        • There's a really neat old Dr. Seuss (yes, that Dr. Seuss) book called "The Tough Coughs As He Ploughs The Dough" that illustrates this quite well.

          And in San Francisco, we have Gough Street, which is not pronounced, as you might guess, to rhyme with "cough" or "rough" or "slough" or "through" or even "dough", but with the "off" in "coffin". Confused he bejezzus out of me the first time I was given directions to "Goff Street".

          Waaaaay off topic: The Seuss book is a collection of his early work, for adults,

      • Very interesting. Where did you get that information about spelling changes?
        • I did a quick Google search. I was aware of the basic fact that Noah Webster initiated many of the simplified spellings, but I wanted to have an exact year and a few more examples. I have to admit that I was not aware of the Chicago Tribune's roll until I did the search.

          What you also might find interesting is Benjamin Franklin's proposed changes to not only spelling, but even to the alphabet. A bold, but failed, effort.
      • *jackass became fmaxwell
  • Many people are partially color blind and are not aware of this fact which would make it impossible to please everyone with your adjustmaents. see: http://home.wanadoo.nl/paulschils/05.03.html [wanadoo.nl]
  • by Ropati (111673) on Sunday February 20, 2005 @11:43AM (#11728657)
    Other posters have gone to great lengths to explain how color perception is environment and beholder dependent. So calibration is of little value. More importantly if you are generating images to be displayed on any users screen, then you have no control over their brightness, contrast, gamma or white balance or the end user's color experience.

    But if you want to calibrate a monitor, I can tell you how I used to do it in broadcast.

    First you set the black of the monitor: Generate a black screen image. Adjust the cut-off for each color so it just barely illuminates the phosphor. When finished, black is barely perceptable and has no pronounced color.

    To calibrate white: Generate a full red screen, 100 hue and brightness, and then use a calibrated light meter to set monitor output to the color temperature of the red component of your final white. Do the same for green and blue. Display an all white screen and see if the screen is proper temperature. Check that the values of black didn't change. Get a feel for where your monitor best performs and run the monitor in a manner that doesn't cause blooming. In other words make sure that the full white value is not beyond the luminance output of your monitor.

    Once black and white are correct, display a black and white stairstep signal. If all the channel gammas are correct, the steps should appear even to the eye and all the steps should be grey. If not, the trick is to adjust gamma of the color you don't see to correct the problem. Gamma correction can be very gross and you might not be able to make every step grey.

    These steps correct the color balance of a monitor, but you still need to check purity, pin cushioning, convergence, horizontal and vertical linearity before you can be sure that the image on one monitor is the same as the image on another calibrated monitor. I can't image why you would go through this type of trouble.

    Of note: The same calibration issues can be applied to audio. Years ago I wired up a new audio system at a recording studio. The studio had done several gold albums including one by the Rolling Stones. All the mics were adjusted to remove bandwidth irregularities. The engineers recorded and set levels for all sessions by listening to the audio from huge JBL speakers set-up with perfectly flat amplifiers. However, when they went to generate the final mix, the did it by listening to the audio through cheap 5 inch speakers. In this manner, they could provide the best listening experience for the majority of users.

  • I don't know what your budget is, but it won't matter if you have same monitors or different ones. Use a colorimeter and it will calibrate your monitors and will create color management files for each of them.
  • by aderusha (32235) on Sunday February 20, 2005 @12:35PM (#11728866) Homepage
    after wading through a couple dozen posts of hopelessly useless pedantic crap, i figured i'd offer a reasonable suggestion: check out the colorvision [colorvision.com] spyder 2 [colorvision.com] calibration tool. it's relatively inexpensive, supports windows and mac, and is widely used throughout the industry for photo manipulation and graphic design workstations. combine with a print scanner, and you can get full start-to-finish calibration of your workflow process. here's a review of the previous model. [dpreview.com]

    as some others have noted you can plan on recalibrating at least once a month, particularly with new monitors. if color accuracy is less important than precision (that is, it doesn't matter if the color is correct as long as it looks the same everywhere), make sure you are using the same model of monitor on each desktop as each phosphor combination used in a given model of tube produces a different color gamut. in all events, stay away from lcd - the gamut is crap and they don't hold calibration well.
    • by ManxStef (469602) on Sunday February 20, 2005 @03:36PM (#11729883) Homepage

      Heh, well said - it's quite surprising how many crap comments there are on this story, you'd think more pro photographers/designers (or their IT techs) would chip in with some decent advise on colour workflow and calibrating to a specific target. Though, as is usual on Ask Slashdot, the submitter didn't provide many details, so it's harder to give him specific information to help him find a solution.

      With regards to colorimeters -- these'll all allow you to calibrate to a "baseline" rather than the best that each device can display -- I've got a Spyder (mk.1) and it's not too bad, though the new ones look much better (increased sensitivity) - though no-one's mentioned so far that the software that comes with these (PhotoCal or OptiCal) requires a seperate licence for each machine they're installed on, so at 30-40 monitors it's not going to be as cheap as it first appears. The GretagMacBeth [gretagmacbeth.com] stuff seems like another good choice (e.g. the Eye-One), as do the Monaco/X-Rite [monacosys.com] calibration tools, but they're more expensive. Ideally you go for a solution that's not just limited to calibrating screens, but can do printers as well, but again it'll cost more (it's usually worth it though - you might as well do the entire loop while you're at it). Or, if he's really serious about it, standardise on the same model of monitor, such as the Sony Artisan [luminous-landscape.com] (with built-in calibration that actually adjusts the CRT guns, rather than just generate a profile).

      Like another poster said, lighting's also an issue, too; hooding the monitors to minimise reflections is usually a good idea, and standardising on specific lighting such as Just Normlicht [www.just.de] fluorescent tubes or Solux [solux.net] halogen bulbs (fed with a specific regulated voltage) helps immensely.

  • by Anonymous Coward

    I am looking for a good way to calibrate multiple monitors (30-40), so that their color looks similar? It seems like everything I find is for profiling your monitor to your printer and scanner.

    "Calibrating" a monitor means adjusting its gun controls until the color output matches a standard for voltage vs. color. "Profiling" a monitor means telling it to output color numbers (r,g,b) and recording the difference between the actual and expected colors for a given color space. The profile also records the

  • If color is important, find a good professional art monitor, and buy one for everyone (or two if they need it). Then buy a color calibration device, stick it on your monitor, and calibrate. This should get all the monitors to output the same colors.

    The real problem comes when you have different model monitors. At the (small) print company I work at, we have different model monitors on every computer. At some point I went around and color calibrated them all, but found that some monitors gave *horrid* c
  • Color bars? (Score:4, Interesting)

    by DaveJay (133437) on Sunday February 20, 2005 @07:42PM (#11731244)
    Once upon a time we used to adjust 20+ monitors in a television control room manually by following these steps:

    1. Send colorbars from the same source (if possible) to all the monitors;

    2. Kick each monitor into blue-only mode, which turns off the green and red guns;

    3. Adjust the contrast, brightness, tint and color (saturation) so that all the bars look the same;

    (You see, color bars are set up so that, when viewed on the blue gun only, adjusting the tint adjusts the brightness of two bars in opposite directions, the brightness another two bars, and so on. To adjust the contrast, you twiddle the contrast knob and look at the two associated bars -- one gets brighter, one gets dimmer. You set it such that the two bars appear to be the same brightness. Repeat for the other controls.)

    4. Pop out of blue mode, and all the monitors look essentially the same. Piece of cake.

    Of course, computer monitors don't come with a blue-only mode, and I believe even component monitors pull the sync signal off of green, so you couldn't just unplug the red and green.

    So perhaps this advice isn't helpful. But if anyone out there is trying to calibrate TV monitors...well, glad I could help. ;)
    • In my studio, we'll often use a stack of blue gels to calibrate monitors that don't have a blue only mode. If you can get a gel (they actually sell filters just for this) that has very low transmission anywhere except blue, you can hold it up to your eyes to do the calibration. Rough, but not too bad...

      Don't forget about doing your brightness and contrast too (see: Pluge Pattern)
  • The solution is easy, buy a woman. They're so much better at telling colours than guys.
  • Have the colors you want to calibrate to printed. Cut holes in printed sheets. Place sheet on monitor. While looking through hole, adjust color on monitor to match color on paper. Repeat on other colors. Repeat on other monitors.
  • Obviously this poster must be from the San Fernando Valley? That's where the teenage girls end every sentence with a rising tone? I guess he can blame the California educational system for his ignorance of punctuation? Oh, well, I guess he'll make it easier for my PDA to pass a Turing test?

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