Monitor contrast vs ...Windows

[kharvatis]

Hello all.

I am using a Windows XP x64 (don't ask!) PC for my professional needs (large format inkjet printing), with an Eizo CG241W and a Colormunki. Always using ColorNavigator of course. So far, and for the past few years, my monitor calibration adjustments (& validation) say that my dynamic contrast is about 1000:1. And this is consistent.

So now I decided to move to Win 7 x64. And now ColorNavigator says that my dynamic contrast is ~800. In every calibration profile I have made. Switching back to the XP installation, contrast is as always: 1000.

Cannot explain it. Any thoughts? 

[D Fosse]

The specs for CG241W says 850:1 native, so Win7 is probably right. I wouldn't worry if the profile seems healthy otherwise.

In any case that seems a little high, especially if you want to evaluate how it comes out in print. 300:1 or 250:1 is more realistic (and even that could be a little high).

Is this one of the models that used a PVA panel? PVA panels are capable of extremely deep blacks, and then it washes out as you view off-axis. Lifting the black point reduces the effect considerably. But in fact Eizo is the only manufacturer I know of who could make PVA panels behave, with a very smooth and wide off-axis black shift (I have one).

[digitaldog]

In any case that seems a little high, especially if you want to evaluate how it comes out in print. 300:1 or 250:1 is more realistic (and even that could be a little high).

Exactly. The inflated spec's of higher contrast ratio are not all that useful in the context of soft proofing. Having a display system that allows precise control over the ratio, to match a print (and build a few of them), is what makes a 'smart monitor' so attractive.

[kharvatis]

My real question is the strange difference in value between the 2 windows versions...

[D Fosse]

Different sensor drivers? Don't know.

If you have a white point luminance of 120 cd/m2, and a contrast ratio of 850:1, that means the black point is around 0,14 cd/m2. I very much doubt you'll be able to get meaningful measurements at such low black levels - which is for all practical purposes pitch black.

[bill t.]

I recall that XP had a system of "color management" dialogues that would let you tweak certain things and make a few adjustments to your color system that were kind of ad-hoc.  Weren't there curves you could adjust?  Have you looked at those?  Maybe Win7 just has better color management.

To get even 500:1 out of my NEC 2690 I need to push it up to about 140 cdm2's, just to get further away from the black point.  Maybe I need a new monitor.

[D Fosse]

Maybe I need a new monitor.

No need. These Eizo PVA panels are extreme, and a black point of 0.14 cd/m² is perfectly achievable if you want it. I've lifted mine to about 0.35 and a contrast ratio of around 300:1, which I'm comfortable with. That also reduces the black off-axis shift to where I don't notice it on this 22" screen.

Most modern IPS panels have native black points around 0.25 to 0.3 at "normal" luminance settings. But there you have the "white glow" in the blacks, equally disturbing on an NEC P232 that I also have.

[kharvatis]

My adjustment targets are at 100cd/D65/2.2. Drivers are obviously the same, as we're talking about the same version of ColorNavigator. I really don't know that to make of these (quite big) differences. Maybe my Munki is getting crazy (or dying )
Btw, I'm getting a black point at 0.07cd.

[Czornyj]

ColorMunki Photo is not reliable at low luminance measurement. Results are not repeatable, and heat has noticeable impact on them.

Furthermore - ColorNavigator has three modes, that have impact on resulting CR - Gray balance, Standard and Contrast Priority:

[D Fosse]

Btw, I'm getting a black point at 0.07cd.

It's probably not only the Munki, I don't know of any sensors that give reliable readings at those levels. My guess is that it's reading effectively zero, and throwing out a more or less random value. I've seen the same with Spyder3 and i1D.

[MiSwan]

Could be whatever. If not the Navigator drivers, it could be anything in the driverchanges for the graphic board between XP and W7. Or as mentioned, the the typical drift of the low blackpoint reading.

You should check what Marcin points you at: Try different setting for the greybalance. Try the "contrast" with both systems (testing only). It will pull maximum range with both with less analyzing of "neutrals" down there.

If there is a newer version of Colornavigator that can be used with W7 and upwards, try it.

You could also run a testdrive with BasiCColor Display 5.2 (14 days full working demo). You'll get options for readings both native and profile active.

As is calibrated and profiled:
Settingtab > Luminance/contrastratio: read black and whitepoints with profile active. Calculated ratio on the fly.

As native without profile in the loop:
Hardware set up > Colortemp will ( a part from CCT) give you native whitepointlevel directly. Make your own blackpatch separately (desktop) and read it instead of the white patch in BasiCColor will give you the native black with profile disconnected. Count the contrastratio on your own.

Personally I think it's simply a diff in the how the XP vs W7 handles the graphicboard. Differences between different system, OS's or calibration apps, is frustrating as hell. X-rite Profiler gives me 10 cd/m2 lower luminance readings than any other application. Why? Opinion or driver difference? It just pisses me off that there IS a diff in a luminancereading and no mentioneing about why anywhere.

The diff between 800:1 vs 1000:1 mean so little at this high levels. Would had been a much larger issue if your're down at 250:1 and having diffs down there when trying to match a papers ratio. You're not matching papers at 1000:1….

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