Identical monitors - different colors

[Alex314]

Hello everyone,

Six months ago I bought a Dell U2412M monitor that produced pleasing colors. Recently I bought a second one and I operate both now in dual monitor mode.
To my amazement the two monitors show different colors for the same image. The desktop background color I set to R 151, G 192, B 151. When I take RAW photographs of a background area of both monitors and I display these in Photoshop CS5, I find the following Lab values (sample size 100x100):
Old monitor: 59, -21, 16.
New monitor: 59, -29, 23.

I expected to find nearly the same values for both monitors. Was that unrealistic? Can this be calibrated away? If so, do I need hardware to do that?

Thank you for any help.

[ggroess]

Alex,
I think you can manage this but it will probably be a manual process unless your video card has separate controls for each output port. 
You are seriously close as it is. 

I'm betting that the adjustment is so slight it might be tricky to realize.  How close are they visually?  Is there one monitor you color correct on?  you might want to just have a primary monitor and stick to that....

Last question Why have you set the monitor background to the RGB you have listed?  it is not a neutral to begin with...
Greg

[Alex314]

Hello Greg,

I was afraid that it would be difficult to get the monitors to display exactly the same colors under general conditions. No, my video card doesn't have separate controls for the ports. I can do it in the OSD of the monitors, but that will be difficult also.

I can see the differences quite well, but then again I cannot tell which one is color correct. I think for the moment I'll stick to one as you suggest.

The reason I have this peculiar background color is trivial: it is not boring as is grey. When I do color correction, I work full screen though.

[ggroess]

Having chatted with Mike Russell and Lee Harper about this one we came back to a few basic things...

1) Pick the newer monitor for your primary color corrections screen.  We feel that it will have a longer life.

2) If you can, rent or purchase a calibration tool and get your monitor into a fairly calibrated state. The calibration tools have specific screens to do this for you. 

If you choose to do it by hand.  Use a three toned neutral color square that can fill the monitor.  This will allow you to better see a color cast in the monitor during the adjusting phase.  White, Grey, Black.  There are lots of web sites that have target images and process outlines to help you figure this out.

3) Test a print against the monitor and your printer to see if your visual adjustments match up to the output you expect. 

4) Expect that the monitors will never be 100% in synch.  Unless you are doing high end processes and can afford to have the monitors calibrated frequently they will always be slightly out of synch...

5) Enjoy the real-estate...

Greg

[Alex314]

Hello Greg, Mike and Lee,

Thank you all for your thoughts and advice on this rather tiny problem. I think I leave it now as it is: since yesterday I have corrected the older monitor slightly and now they are very much alike. No one will see any difference unless you study the colors very carefully. As they are IPS type screens, I have no trouble with viewing angles which helps a lot correcting colors. Thanks again.