Do You Use A PC And An External Monitor To Edit Your Photos? Is There A Recurring Calibration Mismatch Between The Two? I Found A Solution

Summary:  If you don’t want to read this entire post, here is the solution.  Boot up your computer or laptop without your external monitor turned on.  After your computer is completely booted up and running, then turn on your external monitor and switch to “Duplicate” monitor mode.  If I do that I don’t have the calibration mismatch.  For a full explanation, read on.

A few years ago I decided to change the computer hardware system I use to edit my image files.  At that time I had an 8-year old desktop PC and a 5-year old moderately spec’ed laptop.   Also, I had a relatively new and very nice 27” Ben Q 2700SW monitor that I routinely calibrated to more accurately edit my images.  The desktop was used in my home office and the laptop when traveling.  Since both were aging I wanted to replace both computers with updated and more powerful ones.  However, I thought if I bought a very highly spec’ed laptop, I could replace both with a single device for home and travel use.  That also would solve my issue of having my LR Classic catalog on the desktop, creating a second LR catalog on the laptop when traveling and then having to integrate the two after returning home.  Not a big deal, but I’m all for efficiency and easy.

I did just that and it has worked and continues to work very well.  But about 6 months ago I started running into a monitor calibration issue.  I don’t know when it started exactly.  Up until then, I had used an i1 Display Pro to calibrate both the laptop and external monitor separately.  In fact, nothing had changed except the two monitors quit matching.  The laptop calibration is a software calibration at the system level in Windows but the Ben Q calibration is a hardware calibration, using their proprietary PaletteMaster Elements software and is stored and loaded separately.  If calibrated correctly, both monitors should match.  All worked well for the past few years until, as I said, until about six months ago.

What I began to see was a mismatch between the two monitors when using the “Duplicate” screen configuration.  For those who may not know what that is let me quickly explain.  When having a secondary monitor attached to the computer, Windows PCs allow you to 1) use the laptop (or primary) monitor only, 2) secondary monitor only, 3) have both monitors active, called Duplicate and to 4) extend what’s on the primary monitor to the secondary monitor.  An example of that would be when using Photoshop on a desktop computer with two monitors, having all of your menus and controls on one monitor and only the image you are working on showing on the secondary monitor. Back to the problem

Until six months ago, both monitors matched in both color and luminance as well as matching in each of the red, green and blue spectrums.  I1 took care of that.  But all of a sudden what I began to see was the laptop’s monitor no longer matched the external Ben Q’s monitor.  The Ben Q was perfectly neutral in color but the laptop monitor showed a much warmer image.  I recalibrated both and all seemed well, but then when I booted up my computer the next morning, the mismatch occurred again!  …and it happened again and again and again.  After calibration they matched then didn’t the next time I booted up my computer.  In fact, I must have recalibrated those two monitors six or seven times each trying to get them stay matched.  The laptop monitor always turned a warmer tone or, in photographic terms, seemed to acquire a higher Kelvin temperature and not keep the 6500k to which it was calibrated. 

Trying everything, my next step was to see if I could use a built-in Windows or Dell color calibration feature and calibrate it that way (I have a Dell XPS 15 laptop).  I messed and messed with it trying to get the color at 6500k.  Nope.  Same.  I then went in to my display settings and deleted all of the stored color ICC calibration profiles that were there from past calibrations.  I then recalibrated both monitors.  No change.  The Ben Q was perfect but the laptop was too warm in overall tonality.  My frustration level kept rising.

If I wasn’t able to correctly calibrate the laptop’s monitor, I then couldn’t trust it to correctly edit my image files when traveling—the reason I bought it in the first place.  I started to consider buying another desktop and going back to my old routine.

Last week, for whatever reason, I booted up my laptop with just its internal monitor activated (I normally kept it in Duplicate mode).  It looked perfect.  The color and luminance looked dead on.  Neutral whites.  I then switched to the Duplicate monitor mode and it stayed correctly calibrated.  It matched the Ben Q perfectly.  I repeated this again and again and the same thing occurred.  The laptop retained its correct calibration.  Something was happening differently than when I booted up the laptop with both monitors engaged—Duplicate mode.  But what?

Not knowing why my issue was accidentally solved, the other day I called up my personal consultant, ChatGPT, thoroughly explained everything I was seeing as well as the latest revelation and asked it for an explanation and solution.

Here is a partial response made by ChatGPT that explains what is going on:

“What you’re seeing is a known but frustrating quirk of how Windows handles color profiles in a dual-monitor setup, particularly when dealing with:

• Multiple displays with different ICC profiles
• Intel GPU driving both screens (as with your Dell XPS 15 9510)
• Windows 11, which still has flaky multi-display color management behavior

What’s Happening Behind the Scenes

Windows color management isn’t truly per-display. It can assign profiles to different monitors, but some graphics driver configurations (especially on laptops with hybrid GPUs) cause the system to leak or misapply ICC profiles between displays.

In your case:

• When only the internal laptop screen is active, the correct ICC profile is loaded and applied via Intel’s GPU LUT.
• When both screens are active, Windows (or the Intel GPU driver) sometimes incorrectly applies the BenQ’s ICC profile to both displays, especially if it’s marked as the “default” or is reloaded by Palette Master Element or other startup software.

This explains the warmer tone you’re seeing—it’s the BenQ calibration (likely targeting D65 with a native wide-gamut gamut) being improperly applied to your laptop’s more limited sRGB panel.”

Since my laptop has two GPUs in it (a processor mounted Intel and an Nvidia), the system seems to be misapplying the calibration when it boots up with both monitors active.  ChatGPT gave me three relatively complex solutions to fix this but, instead, I have chosen to just boot up my laptop with only the laptop monitor active, then switch to dual monitors afterward the computer is completely booted up.  This has worked perfectly.  When shutting things down at the end of the day, I quickly and easily reverse the process.

I post this for general information and to help those of you who might be experience in the same issue.  I certainly don’t know if any issue you have will be solved by this or is occurring because of the Windows system improperly loading ICC proifiles, but it might be helpful in some way.

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Thanks for looking. Enjoy!  

Dennis A. Mook  

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