# Dual Monitors Calibration questions



## Schroedingers Dog (Oct 10, 2008)

Hi,

I have a Samsung SyncMaster 245BW and a Syncmaster XL2' connected to a Vista system.  I use a Spyder2Pro to calibrate the monitors.  

The result is perplexing.  While the colors are close, the 245 is significantly brighter than the XL2'.  I used the advanced options to set the brightness and contrast on both.

How do I know which monitor is correct?  

I mostly take photos of High School sports and provide them to the students and parents or more concisely my goal is not to print.

Should I print and see which screen is closer to the print version?  I tried using auto correct in LR2, but that does not consistently point to one monitor over another.


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## Brad Snyder (Oct 10, 2008)

We've had multiple discussions on this topic, and at this point I'm not entirely clear whether Windows is capable of maintaining two separate monitor calibrations. Personally, I believe it is, provided you are driving them from two separate video cards, or have a video card with dual LUTs (look-up tables) specially designed for separate monitor calibrations.

That said, I surely would love to hear the definitive answer.


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## Halfje-Bruin (Oct 10, 2008)

The Spyder2 is not capable of calibrating 2 monitors. Also, as Brad already mentioned, you need a videocard with dual LUTs or 2 videocards for proper calibration. If you have 2 LUTs than it is possible with some tricks to get proper calibration of 2 monitors:

- calibrate each monitor on the proper videocard (use a single card in the PC each calibration) or as the primary monitor
- use the Microsoft Color Management tool to assign the generated profiles to the correct monitor
- remove ProfileChooser from the start-up folder


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## billg71 (Oct 22, 2008)

Halfje, I beg to disagree, the Spyder2Pro profiled(not calibrated) two monitors in two of my systems perfectly well. Both systems had mid-range Radeon graphics cards, a 13xx and a 195', respectively. It worked fine with two monitors from different manufacturers, and later with two monitors, same model, same manufacturer. After profiling with the Spyder2Pro both monitors were very different before the profiles loaded and almost identical afterwords.

But that's irrelevant to Schroedinger's question..... SD, are you setting both monitors to the same luminance when profiling? If so, given that the 24" Samsungis a low-end consumer monitor, I'd tend to trust more in what I see on the XL2'. Consumer-grade monitors are notoriously "hot", I used to profile my Viewsonic VP-93'b's at 1'' cd/m2 to get a good print match, my NEC matches just fine at 14'. But the one NEC cost more than twice as much as the two Viewsonics, a good example of getting what you paid for......

Brad brought up a good point, if your video card doesn't support dual LUT's you're pissing into the wind trying to get both monitors to look the same. If that's the case, profile for the XL2' and don't worry about what the 24" looks like. Evaluate your images on the best monitor and go on from there, use the other one for Word and Excel.

HTH,
Bill
(P.S.  Like your handle! But it was a cat IIRC, wasn't it?)


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## Halfje-Bruin (Oct 22, 2008)

billg71 said:


> Halfje, I beg to disagree, the Spyder2Pro profiled(not calibrated) two monitors in two of my systems perfectly well.



I was talking about the Spyder2, not the Spyder2Pro. The software is not capable to handling multiple monitors.

I now have the Spyder3Pro and it is possible to calibrate both monitors but as I only have a single graphics card this is not helpful. I'm still looking for a nice PCI express 1x card for my second monitor.


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## Ruahrc (Feb 7, 2009)

How do you know if your video card has dual/multiple LUTs?  I have never seen this listed in the specs of a video card, but I admit I have not been keeping up with video cards that much lately.

I also seem to recall this being an OS specific issue not a hardware issue.  Something like Vista not being able to do dual LUTs or something, until SP1 was released?  I'm on a mac so I don't know, but also have never heard of these LUT problems on OS X.  Is this true?

Norman


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## Scott O (Feb 7, 2009)

To me, the way Adobe adopted dual monitor use in Lightroom was close to useless.  I had hoped it would be done in the way they did it for Photoshop, that is, allow floating menus to be put on one monitor and keep the graphics on the other.  Even though I am able to calibrate both monitors, they are not exactly the same so most of the time I just turn this feature off.  Now maybe if both of my monitors were the same and both top quality my opinion would change...


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## Brad Snyder (Feb 8, 2009)

I'm currently using two video cards, running 3 monitors on XPSP3. The two primary identical monitors are connected to separate cards, and are calibrated/profiled individually. The third monitor is not color critical, and just assumes the profile of one of the others. 

I know I have 2 LUTs, because of the 2 cards.  Like you, Norman, I'm finding spec info on dual LUT cards hard to come by on casual googling. 

And as you say, Mac is somehow different in a way I haven't looked into.


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## thisbejonas (Mar 2, 2009)

Im getting two Dell Ultrasharp 22'9WA monitors and have been really digging around trying to find out what I need to do to calibrate both monitors. Currently I have a Nvidia Geforce 79'' GS with dual DVI ports. Here lies the problem with the dual LUT issue, I have the spyder2express will that allow me to calibrate my new monitors or do I need to run dual video cards as well and what type of cards should I get I have 3-"PCIE-X1" slots, 1- "PCIE-X16" and 3 regular PCI slots. So I am completly lost on the best way to achieve calibrated dual monitor setup. Any help greatly apreciated.


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## Halfje-Bruin (Mar 2, 2009)

I don't think the Spyder2Express allows you to calibrate 2 monitors but you can calibrate one monitor at a time. To load the profiles you can use a Microsoft tool (I don't know the name) instead of the Spyder software.

Just try this with your current video card but you might want to consider that Lightroom will only use the profile information from the main screen and not of both screens when the second display is used. Somebody, please correct me if I'm wrong with this.


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## Brad Snyder (Mar 3, 2009)

Jonas, Welcome to the Forums. Kees is correct as far as he goes. I can't testify to Spyder2Express, but I think you should be able to use it in conjunction with dual monitor calibration. I'm using Color Munki.

You will definitely need two video cards.  (As you say, there supposed exist dual output cards, with dual LUTs, lookup tables, which would enable dual calibration on one card. For some reason documentation and specifications for such cards is hard to come by.)

The cards need not be identical. I'm currently running 2 nVidia GeForce 55''s, one on an AGP slot and one on a first generation PCI slot. (Antique gear, I know). So, you can certainly save money, and reuse your current adapter, and just add another. How much you spend, and what slot you use, will depend on what sort of frame rate performance you need. Gamer? Go big/fast.  Lightroom & PS don't really stress a video card. (CS4 does provide some graphic processor acceleration, I believe, but don't have any experience to offer there.)

The method is to use your calibration profile generator to profile the first monitor, and assign the profile to that adapter/monitor pair. And then repeat the calibration with the second pair. Careful naming conventions will help keep this organized.

Both the standard Display Properties dialog and the Windows Color Management Applet, see here, will allow you to assign different profiles to different displays. (Note, with only one dual output video adapter, this strategy falls apart here, as the most recently assigned profile will be assigned to both displays).

I've attached screenshots of the Color Management Applet showing the different profiles assigned.


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## Schroedingers Dog (May 20, 2009)

Time for an update:

1) The dual headed video cards that are capable of supporting separate LUTs are generally marketed and sold as graphics or 3D graphics workstation cards.  They are, for the most part, expensive and the one that I found that was in the range of reasonable turned out to be painfully slow.

2) I also have two different video cards.  I've heard that identical cards can cause problems with the assignment of profiles.  Does anyone know if this is correct?

3) My saga continues...Since I first posted my problem, I've gone through/upgraded to 3 new video cards (including the workstation card), a new motherboard, new cpu, and I've upgraded to the Spyder 3 Elite. Yet, I still have calibration problems.

Following the instructions of the Spyder 3, I calibrated both monitors.  I receive no errors or warnings and all indications are that the monitors calibrated successfully.  I've verified that each monitor has its own profile.  Now here's the part that baffles me - despite the fact that the monitors have calibrated, there is a noticible difference in the colors of the two, especially towards the reds.

What I don't understand is how the same device can 'successfully' color correct two monitors and have the results be noticibly different.  

It seems to me that the 245 is closer to what I think is correct than the XL2' which is not what I would have expected.  I've not resolved this problem, but I've reached a point I can tolerate by setting the mode on the XL2' to adobe RGB and NOT profiling the monitor.

Not surprisingly, Samsung points me towards Datacolor and Datacolor says it's Samsung.

Any one have any suggestions or thoughts on why this is happening?  In particular, I'd love to understand how an external color sensor (the Spyder 3 elite) can verify that the two monitors are calibrated yet the results differ.  I could understand if it reported differences and told me that one or the other could not be adjusted, but how can it say they are profiled and yet still appear different?  

My mind boggles.


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## Brad Snyder (May 21, 2009)

Dog, I started an answer, but I see I don't really have anything to add to my post above. My video cards are as close to identical as they can be while running on different slot types, and I haven't encountered any difficulties.

Are you using Display Properties, or the Color Management applet to assign the profiles? (Don't think it matters, just curious if you see the same results either way)


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## sizzlingbadger (May 21, 2009)

This may not be of much help but.... I had a Samsung monitor 433BW (or something similar) and it was useless. It had some kind of active/dynamic enhancement and it never looked right even if I turned that option off in the menu. I sold it after a few weeks and when back to a single display. It's also possible to calibrate multiple monitors with even the basic Spyder Express - you just have to know where it creates it's files and then you can re-name them and then assign them to a device (at least on a Mac anyway).


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## Pati (May 24, 2009)

sizzlingbadger said:


> This may not be of much help but.... I had a Samsung monitor 433BW (or something similar) and it was useless. It had some kind of active/dynamic enhancement and it never looked right even if I turned that option off in the menu. I sold it after a few weeks and when back to a single display. It's also possible to calibrate multiple monitors with even the basic Spyder Express - you just have to know where it creates it's files and then you can re-name them and then assign them to a device (at least on a Mac anyway).



Can you provide instructions on how to re-name Spyder2Express files or provide a link with instructions?

I want to calibrate my MBP and Dell 22'9WA monitor with a Spyder2Express.

TIA


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## sizzlingbadger (May 25, 2009)

1) Set monitor A as the main display in system preference and run Spyder2Express.app

2) An icc profile named "Spyder2express" is created in "/Library/ColorSync/Profiles/"

3) rename this file as "Spyder2express_monitorA"

4) right click and open the profile in Applications/Utilities/Colorsync, rename the 3 localized description strings to match the new file name (see attached image for a screen shot)

5) set monitor B as the main display in system preference, run Spyder2express.app again.

6) A new icc profile named "Spyder2express" is created at "/Library/ColorSync/Profiles/". Rename this file "Spyder2express_monitorB"

7) right click and open the profile in Colorsync, rename the localized descriptions strings to match the new file name (see attached image)

Now under System Preferences/Displays/Color  you can select the seperate profiles for each monitor.

Note: The name you give in the localized settings dialogue in colorsync is what is displayed in the Displays/Color dialogue which is why you have to rename them and not just the icc profile files or you can't tell which profile is which you will have 2 with the same name.


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## sizzlingbadger (May 25, 2009)

p.s.  you don't have to rename the 2nd profile, you can just select the standard Spyder2Express profile for monitor B if it save some time. Also you can call the files and localized strings anything you want, like the monitor name/model for instance.


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## sizzlingbadger (May 25, 2009)

Schroedinger's Dog said:


> What I don't understand is how the same device can 'successfully' color correct two monitors and have the results be noticibly different.



The calibration can only correct so far. I have seen this problem with cheaper monitors and also my own Samsung display. It was quite different to my Apple display even after calibrating both of them. Better quality displays will give more consistent results.

If the monitor is a long way off to start with then you can lose some of the dynamic range when it is calibrated, much like under exposing an image and then trying to bump up the exposure in an editor.

If you want to know practically everything there is to know about colour management then check this out   http://www.gballard.net/psd.html

Cheers Nik


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## Pati (May 25, 2009)

sizzlingbadger said:


> 1) Set monitor A as the main display in system preference and run Spyder2Express.app
> 
> 2) An icc profile named "Spyder2express" is created in "/Library/ColorSync/Profiles/"
> 
> ...



Thanks for the easy to follow instructions.



sizzlingbadger said:


> p.s.  you don't have to rename the 2nd profile, you can just select the standard Spyder2Express profile for monitor B if it save some time. Also you can call the files and localized strings anything you want, like the monitor name/model for instance.



I was thinking of doing this when I read the instructions.

Thanks again.


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## Schroedingers Dog (May 27, 2009)

sizzlingbadger said:


> The calibration can only correct so far. I have seen this problem with cheaper monitors and also my own Samsung display. It was quite different to my Apple display even after calibrating both of them. Better quality displays will give more consistent results.
> 
> If the monitor is a long way off to start with then you can lose some of the dynamic range when it is calibrated, much like under exposing an image and then trying to bump up the exposure in an editor.
> 
> ...




Hi Nik,

Forgive me, I worded my question poorly - If the calibration device is external, and reads the actual color displayed, how can it report that the two different colors produced by the two different monitors are correct?  At least one of them must be wrong, right?

-Mike


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## Schroedingers Dog (May 27, 2009)

Brad Snyder said:


> Dog, I started an answer, but I see I don't really have anything to add to my post above. My video cards are as close to identical as they can be while running on different slot types, and I haven't encountered any difficulties.
> 
> Are you using Display Properties, or the Color Management applet to assign the profiles? (Don't think it matters, just curious if you see the same results either way)



I've tried both.  Same or similar results.  It is good to know that you haven't had problems with the two identical cards.


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## sizzlingbadger (May 28, 2009)

Schroedinger's Dog said:


> Hi Nik,
> 
> Forgive me, I worded my question poorly - If the calibration device is external, and reads the actual color displayed, how can it report that the two different colors produced by the two different monitors are correct?  At least one of them must be wrong, right?
> 
> -Mike



No, they can still look different depending on the monitor quality and technology. The calibration device is not the same as the human eye either so can only calibrate certain aspects of what you perceive.


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## Schroedingers Dog (May 28, 2009)

Does that mean that when the sensor reads a color, it is looking for an acceptable range of values instead of a single one?

How then can it tell that there is something initially wrong with the calibration?


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## Brad Snyder (May 28, 2009)

I think it's more an issue of the display device not responding correctly (linearly, etc.) to a correctly determined calibration.

The profiling software sends out predetermined signals to the display, and the gizmo reads the actual result. The software then calculates how to tweak the output signals to make the actual result result match the desired result. I don't think there's a 'feedback' step where the actual and desired are re-compared. Hence, the color error can be determined, and the fix calculated, but it's possible the display can't actually produce the 'fixed' color. Combine two displays side by side, and these (possibly minor) problems/errors can really emphasize differences between the two.

Take this with a grain of salt, most of this, is partially-educated speculation, not a Bruce Frasier/Jeffrey Friedl/Jeff Schewe detailed *analysis*.


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## sizzlingbadger (May 29, 2009)

Brad is correct. There are so many factors that have to be taken into account. Calibrate a glossy display and matt display and they will look different to the human eye even if the colour is correct. The surface texture of the display, thickness of the glass etc all make differences. Many calibrators can't account for the ambient light that mixes with what is displayed, this varies according to the surface of the display and the view angle, distance etc...

High quality displays will look similar (that's what you pay for) but so many displays out there are just not designed or manufactured to display colour accurately. Many display manufacturers use different panels in their displays even with the same model number. Samsung are a good case in point for this. The model I had was supplied with 2 different sources for the LCD panel. One was quite good but the other was horrible. I had the horrible one,  the only way to tell as to look up the serial number to see where the panel supplier came from.


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## Schroedingers Dog (May 29, 2009)

That now makes sense.  

I wasn't questioning the monitor's ability to accurately produce colors, just the Spyder's reporting of the two monitors as successfully calibrated.

Given that there is no feedback loop to ensure that the monitor's response to the calibration is never verified, would multiple calibrations, with no resetting of the monitor eventually produce a better result (given all the limitations mentioned above)?


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## Brad Snyder (May 29, 2009)

That one's over my head. I dunno'....


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## Denis Pagé (May 29, 2009)

Schroedinger's Dog said:


> Given that there is no feedback loop to ensure that the monitor's response to the calibration is never verified, would multiple calibrations, with no resetting of the monitor eventually produce a better result (given all the limitations mentioned above)?


No. The reason is that the profiling software is not calibrating the monitor _(except on some monitors designed with their own profilers)_ and that they start by deactivating any monitor profile in use before starting their job. So, you always start from the same point unless you change settings on the monitor's OSD.


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## altendky (Jun 4, 2009)

Schroedinger's Dog said:


> how can it report that the two different colors produced by the two different monitors are correct?



Disclaimer: I do not have any experience with colorimeters, just ran across the thread while researching purchasing one. :]

But I do think I can offer some theory and maybe even a few links.  Your eyes have three unique types of photo sensors each with a particular frequency sensitivity profile (Wikipedia: Physiology_of_color_perception) and I think that each creates a single luminance only signal to the brain.  I believe that colorimeters work like this as well, though they may well use more than three sensors (Wikipedia: Tristimulus_colorimeter, only really reference for the concept, not proof that the Spyder-whatever for example works that way).  And even another point is the light source.  With a CRT you get another trichromatic system with it's R, G and B phosphors each with their own frequency emission profile.  In the case of LCDs you have the trichromaticity of the R, G and B sub-pixels but additionally the backlight has yet another spectrum to introduce!  Which, of course, would be different for CCFL vs LED.  After all these spectrum emissions/responses get mixed together there is plenty of room for variation.  I've heard that wide gamut displays can 'confuse' colorimeters as well, though I didn't look up your models to check if that would even be applicable.

...  then ...  your brain and the colorimeter software must mix the multiple signals back together and reform the concept of a single color.  What a mess, can't wait until displays are capable of emitting arbitrary spectrums from each pixel (like that will happen anytime soon).

As to others comments about the single calibration cycle, I would certainly agree that could be just as problematic (or maybe my above description is 1% of the problem and this is the other 99%).  Still, some systems do provide at least a report of the quality of the calibration (Lacie Blue Eye Pro).  Again, I don't know off-hand if that is the case with the Spyder2 Pro (what you have IIRC).

Regardless, best of luck getting it all resolved.  If my experience thus far holds, I'll be needing lots of luck too.

-kyle

Recap:  The two monitors are not capable of creating the same spectrum.  The colorimeter will tweak the colors sent to the monitors such that it expects the corrected values will result in emissions from each monitor that it will interpret as the same.  It may not be very successful at that (due to not repeating the cycle to identify the remaining error) but regardless your eye and brain can interpret the still different emissions from each monitor differently than the colorimeter anyways.


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## Schroedingers Dog (Jun 4, 2009)

> I've heard that wide gamut displays can 'confuse' colorimeters as well, though I didn't look up your models to check if that would even be applicable.



One of my monitors, the XL2' is wide gamut.  The other is not.

I had not heard that wide gamut displays are problems for colorimeters, but it doesn't surprise me.  When I spoke with Customer Service for Datacolor, they recommended I set the monitor to sRGB mode and basically not profile it at all.  That is where I am right now.


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## sizzlingbadger (Jun 5, 2009)

Schroedinger's Dog;46'23 said:
			
		

> I had not heard that wide gamut displays are problems for colorimeters, but it doesn't surprise me.  When I spoke with Customer Service for Datacolor, they recommended I set the monitor to sRGB mode and basically not profile it at all.  That is where I am right now.



That is probably someone at Datacolor without the knowledge. Many high quality displays are wide gamut [usually Adobe 1998] and will calibrate fine.

Why would people spend all that money on a wide gamut screen and then set it to sRGB, it makes no sense.


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## Halfje-Bruin (Jun 5, 2009)

I upgraded my Spyder2 to a Spyder3 as the old Spyder2 has problems with wide gamut displays and the Spyder3 works just fine. I have a HP 2475w and like it.


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## Denis Pagé (Jun 5, 2009)

And X-Rite is giving specific instructions for the ColorMunki with the HP Dreamcolor wide gamut monitor.


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## Denis Pagé (Jun 5, 2009)

Isn't it simpler to calibrate only one like the not so cheap Nec CRV43 ? :roll: :shock:


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## lhodaniel (Jun 8, 2009)

I'm using a Samsung XL2' and 2'4T in a dual setup under Vista 64. The video card is an ATI 26''XT with dual LUT's. I use a Spyder 3 Elite. One problem you have with any Spyder 2 on the XL2' is that it is not recommended (by Datacolor) for wide gamut monitors. The Spyder 3 is.

I get a virtually perfect match by calibrating the XL2' using Samsung's Natural Color Expert. It isn't supposed to work with Vista 64, but I have had no problems using XP Compatibility Mode. By using this, I can use the XL2''s programmable internal LUT to calibrate it to 65''K G2.2. I then use the Spyder 3 Elite software to match the 2'4T using the Studiomatch feature.

Lloyd


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## jimb (Jun 10, 2009)

I have the same problem as the original poster.  Two monitors calibrated, with one ending up more red (pink) than the other.  I have a dual head nVidia.  I have calibrated with a Spyder 3 and a Eye-One Display 2, with various settings, and even tried a third party calibration program.  The result is always the same, so I imagine it's just not possible to make them match.

XP, Dell 22" and 19" Ultrasharps. MS Color Applet

P.S.  I find that the Eye-One results in a overall more neutral white and gray than the Spyder.


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## Denis Pagé (Jun 10, 2009)

I suggest you calibrate the monitor(s) before profiling them.

For example, recucing the red channel on the pinkish one and then profile again with Spyder/Eye-One.


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## Brad Snyder (Jun 10, 2009)

I'd say verify that the nVidida is capable of dual calibration. Dual head does not necessarily imply dual-LUTs.  

If you're sure, then ignore this.

Oh, and Welcome to the Forums.


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## jimb (Jun 10, 2009)

It's Nvidia 86'' which does not show two monitors in the device manager, so I guess there is only one LUT.  But the two monitors do show the affects of their profiles separately.  I managed to adjust the main monitor to a good result by setting the color temp. to 68'', which I know is wrong but it takes the color cast away. I then manually tweaked the second monitor to match.  It's close enough to not be annoying at least.  Now if I can just get the printer to match reasonably well.


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## Denis Pagé (Jun 10, 2009)

jimb said:


> ...Now if I can just get the printer to match reasonably well.


The ColorMunki made miracles for me on this point and gave me more with color sampling abilities.


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## Schroedingers Dog (Jun 12, 2009)

A couple of points:

1) I'd double check that your single, dual-headed graphics card is capable of supporting separate LUTs.  From the research I did (primarily on ATI cards) only those marketed as for graphical workstations supported this feature and I can state as fact that the less expensive ones run VERY slowly.

2) Lloyd.  I will try your suggestion, as our setups sound very similar.  I had no luck trying the Samsung software and Samsung wasn't much help either.  I didn't try 32bit compatibility.  Sounds promising.

3)  I used the Spyder 3.  I have the Studio version and I'm very pleased with the printer profiling results.  

4) I tried the 'one monitor calibrated and the other not' approach but it is harder than it sounds.  It could be just me, but having the two monitors showing significantly different colors was very annoying.

5) I'm curious - which color calibration tools verify the results (second pass)?  It seems that the Spyder 3 does not.


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## leuallen (Jun 15, 2009)

Perhaps not germain to your experiences with calibrating dual monitors, but I will give my experiences. I just purchased a new high end Window PC and your discussion had me worried that I would have trouble with my dual monitor setup. Not so, it went very smoothly.

A new Vista 64 Sp2, I7, 12 GB, ATI 485' with a new NEC 269' Spectraview. Used existing Mitsubishi Crt and Eye One Match software for second monitor.

The NEC calibrated very easily with its puck and software. Picked the correct monitor automatically. Saved profile with defaults.

Switched to Eye One software with my old puck. Picked the correct monitor automatically and calibrated. Saved profile with "... Mit" appended to name, otherwise defaults.

Everything looked fine. Checked Color Management from control panel and it showed each monitor with the correct profile. Single video card, no dual LUT's or anything special. I wonder if the fact the the NEC writes directly to the monitor hardware rather than a LUT had anything to do with my success. Or maybe using two different calibration programs, or maybe the planets were aligned correctly?

Anyway, quite relieved and happy. Just wanted to let you know that it is possible to calibrate dual monitors without any fancy footwork.

Larry


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## Denis Pagé (Jun 16, 2009)

In your case, I would say that you calibrated the NEC and that you profiled the Mitsubishi...


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