I have been working for some years trying to get consistent color management with a MacPro 17" laptop and external color monitor. I run into a variety of issues, from small ones, like the external monitor using the profile for the internal after waking from sleep - to big ones, like total shifts from day to day where the profile for the external seems to be changed or corrupted. I am curious to know if many photographers are using Mac laptops in a color managed situation - or do people shift over to towers for critical work?

Yes, this seems to be a bug in Leopard and, if I remember right, Tiger too (haven't test SL on a laptop yet) and a lot of people suffer from it. It becomes second nature to check ColorSync Utility to see which profile is being used as the default.

I've never come across the big problem you list here but have come across situations where small movements in the cable and connector affect the colour of external displays when a VGA connection is being used.

Laptops seem as popular as ever, with gamuts and contrast improving (you'll probably have seen Rob Galbraith's recent article) if you can accept the speed trafe-off.

The second problem you mention, though, is a deal-breaker and needs further investigation.

I regularly use a MBP connected to a secondary display.

The only time I have problems with display profiles getting mixed up is when I have done a software update, or when a 3rd monitor gets involved (such as a projector).

while I check things frequently, it seems that when I find a problem I can almost always remember one of these two things happening a day or two prior to having problems.

I have been connecting a laptop to a large external display on a daily basis for the last 6 years so this hits close to home.

Apple's laptops have a "clamshell" mode that allows a person to use use his/her laptop with an external display, keyboard and mouse while the lid is closed. This mode makes it easy for mobile professionals to switch their desktop enviornment and the road. The advantages are:

1) Saves countertop space
2) Remembers the correct icc color profile for each display
3) Remembers desktop icon positions between displays
4) Increases laptop display lifespan by staying off in clamshell mode

To enter clamshell mode and connect to external display:

1) Start with a closed, sleeping laptop.
2) Connect power cable.
3) Connect all other cables (the order is not important).
4) Connecting any USB port will wake up the computer.

To leave clamshell mode and disconnect from external display:

1) Open the laptop screen.
2) Select "Detect Displays" from the Displays menu bar (requires that you check the "Show displays in menu bar" checkbox in the Displays System Preference Pane)
3) Then quickly pull the video cable while it is still detecting (this will move all windows and icons over so you won't loose anything)
4) Disconnect all other cables (order is not important)
5) Shut laptop to put it to sleep.

I've been following this procedure for 6 years and it never forgets which profile is for what display. I also use the laptop with several projectors every month as I travel. Of course, you may not want to use clamshell mode but I thought it would be worth mentioning nonetheless.

It's also worth noting that your display calibration software's LUT loader can contribute to display profiles loading correctly after a restart (and system updates). Some LUT loaders are more reliable than others, but I've found Color Eyes Display Pro's to be particularly reliable across a variety of systems.

I use a MacBookPro with 20 inch Cinema display with the Cine as the main screen ( It has the menu bar). Sometimes have had an issue with corrupted system ColorSych prefs which has caused the main preview window in Capture One (3.7x) (OS 10.4x, 1.5x)to use the Laptop screen profile instead of the Cinema Display profile (big problem). I check for this regularly in C1 by opening an image in ColorEditor (Image>Open In ColorEditor). The window which opens contains a confirmation of which profile C1 is using. I don't know how if this affects other apps or how you check for this in those apps. But since is system level, I would think it would be trouble not just in C1.

The solution has been to delete the system ColorSync prefs, which involves opening Apple's Terminal utility and typing in some very specific sequences of characters. The ColorSync prefs get rebuilt on subsequent reboot. Instructions for this are at phaseone.com> knowlege base, and search for article 1715.

The cause of the corruption I believe is connecting or disconnecting the Cine and the MBP while they are running. Not positive about this (Apple says you can do this "hot swap"), but I don't run across the corruption issue if I never hot swap and if I have done a hot swap by mistake have instantly had the corruption issue. Hope this helps? -Ben

Here's a guess as to the cause of your problem based on my experience dealing with a wide range of various brands of third party displays hooked to a 2000 Mac laptop, 2004 iMac and an old 1998 Mac desktop tower throughout the years researching this stuff.

And this guess is based on my noticing third party displays always communicating with the Mac OS from 8 through X upon first connection in getting the OS to write a default profile with the display's brand name and model even though no profile with that name was on the system before the display was connected nor was physically assigned by the user within display preferences.

This is an automated process that happens when connecting any new display where the profile data used by the OS to build the profile is taken/read off the display's ROM chip which is often written in a (hopefully) standard machine language based on EDID (and Apple) specs.

The issue here is that not all third party displays communicate nicely with the OS in this manner and in the process of connecting and disconnecting these displays whether hot swapping or not, things may get nasty.

I've had these default profiles become corrupted, refuse to fully disengage from the vLUT among a few other mysterious unexplainable things.

Have to say I've never encountered your problem, but I mention this quesstimation to illustrate some possible causes and to show how sensitive and finicky things can get when devices communicate between each other using questionably written code. This may be an OS or display issue or both.

You might try another display and see if it does the same thing. If it doesn't then it is a display issue and if it does then it's more than likely an OS and/or the way the profile was written by the calibration package issue.

I appreciate the many good ideas and suggestions. After two hours on the phone with Apple support I concluded it was time to give up laptop color with external monitor. Seems that during 2008 Apple sold an evolving variety of 17" MacBooks. Some use two color cards, some make both displays share one card. The Apple fellow had never heard of Color Munki, which is what I am using for hardware profile. He made many suggestions, none of which helped, but which left me with many problems to solve, like re-establishing hundreds of critical prefs whose loss crippled my softwares.

The problem devolved into a worse one: every time the computer went to sleep or was restarted, the monitor would turn dark and yellow. I could cure it by a fresh profiling, which meant profiling each time I sat down to work.

No help from Apple, because LaCie and Color Munki are third party. No help from LaCie because my LaCie sensor has been in repair for some months and they won't discuss Color Munki. No help from Color Munki because they don't respond.

No help from my local dealer and color management consultant. (They did offer to sell me a nice new $5000 top of the line tower Mac.)

So I went out and bought a used tower Mac fo $1700, spent the day fighting through re-install of Adobe CS Premium Suite and Lightroom. New system is much faster than my laptop, and one day when I get my Blue Eye back, I will profile the monitor and can get back to work.