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skibum5
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Re: Why Color Profile?


Hrow wrote:
I have a thread running here on a calibration issue that specifically mentioned ColorMunki. I am starting a follow-up thread in the hopes of making this a more generic question. The original thread reads in part....

Just got a ColorMunki Photo. I have a two monitor Mac Pro with one 20" Cinema Display and a 24" Cinema HD. I have calibrated both using the same settings, however, the 24" is about 3/4 stop darker than the 20". Have repeated the calibration process a number of times. Same result.

I just heard back from X-Rite support and their response in part was...

When you calibrate multiple monitors to match each other, they may match closely but not exactly which can be extremely challenging for any photographer using dual displays in their workflow for color critical work. You may especially notice a change in cases where you are using a mix of backlighting technologies however even the same model and make of display can render results that may not be a spot on match as the manufacturing can have variables also that might affect these results.

Now the question(s) becomes...

1.Why calibrate a monitor if each monitor is going to look different (3/4 of a stop is a big difference in my mind)?

2. Isn't it the point that they are adjusted to be the same? If they are different, then how do you come up with consistent print output - other than trial and error?

3. If it is trail and error, why do you need to spend money on a calibration device?



Usually the brightness reported wouldn't vary so much but maybe one of them has such extreme and thin peaks in the primaries it's not reading the brightness correctly??

Also if a lot of corrections need to be applied the calibration program may end up needing to lose some top end brightness, so when using a monitor that needs certain types of tone curve corrections you may need to preset the monitor to a higher level and then it calibrate it down to what you had wanted otherwise it won't have room and it might make it darker.

And some software tells you to try to adjust brightness and some doesn't bother to mention that and some tries to fine tune it, if possible, itself a little, it depends what program you are using too.


Aside:
It is true that even if the probe reads the same values on different monitors they may look different to the eye, especially when you compare wide gamut CCFL to CCFL or even to LED since the primary colors have different spectral spikes which might be partly missed by a spectro not costing $$$$$$$$$$$$$$$$$$$$$$$$$$$$ since they may be too thin for it's precision and even regardless of lot the general metamerism issue and the way the spikes in the primary colors spectrum are can alter a human's sense of what color is being shown by a simple R,G,B combination.

The simple 3 stim R,G,B color model is actually too simplistic and can never work to allow someone to see the same photo across different screen types exactly the same way. Even moreso it can't even be corrected for although some monitor try to offer special matching transformations since each individual's eyes have a slightly differerent response to the various spectral peaks in the primaries and one person might see a certain pic look the same one some wide gamut and some sRGB monitor and another might seem some differences and another might seem some differences only in a different way.

The onyl way to get around that would be to go an entirely new form of color management which would be spectrum based and require detailed spectral measurements and then you'd tune the energy at each part of the spectrum and apply correction as needed and then you could get everything to look the same to everyone across all the technology types. I'm not aware of any software/hardware outside of a research lab that takes this approach.

If I make a grayscale chart measure the same on a wide gamut and sRGB monitor and then compare to chart in real life viewed under as close to D65 as I can get, sadly all three don't really quite look the same to me viewed side by side. I see a clear difference between sRGB and wide gamut monitor even though probe says they are the exact same since the eye has a complex response. It is a bit worrisome since then what happens if I ever had to move back to sRGB monitors only or what if the spikes on the primaries of the next OLED tech look different? Then all my careful colro tunings will look different? Anyway to my eyes at least what I see on my wide gamut display actually looks closer to what i see with the real world chart than what I see on my sRGB monitors so to me the way my eye reacts to the wide gamut monitors seems more true to life to me.



Dec 17, 2011 at 06:38 PM



  Previous versions of skibum5's message #10174430 « Why Color Profile? »