Warm Up Before Calibrating

by James Duncan Davidson

I've written before in this blog about the importance of calibrating your monitor. The general message of those articles is: The calibration tool that you use is less important than the act of calibration itself. In fact, the only way to really know what you are doing when you are using Aperture is to use a calibrated display. If you've already spent the money on a computer, digital SLR, memory cards, and Aperture, then you really should get a calibration device so that you can get the most out of your system.

There's something in those posts that I neglected to mention, however. And that is to let your monitor "warm up" for a while before calibrating it. Even LCD monitors need time to reach a steady state after you turn them on. I assume that the biggest reason you need to let them warm up is that the backlights take a bit of time to get up to their operating levels.

I experimented with this last night while setting up my trusty 23" Cinema Display on my girlfriend's new MacPro. She wanted to see how the 23" Cinema display works out on her desk and, in exchange, I get to play with one smoking hot machine for a while. After placing the display on her desk and hooking everything up, I ran an initial calibration. In addition, I used a feature in the Eye-One Match color calibration software that allows you to set a target luminance. In this case, I set a target of 120cd/m2. As you would expect, after calibration, the colors on the display looked better and slightly more neutral.

Then, after leaving the display on for a couple of hours—I had to go into the Energy Saver preferences panel to keep the monitor from going to sleep—I re-ran the calibration. Most interestingly, when I checked the brightness of the monitor that I had carefully set to the target in the first calibration, it now registered almost 170cd/m2. So, I backed the brightness down to reach the target of 120cd/m2 again and re-ran the calibration. After calibration, I compared the two profiles. Two things about this comparison were interesting. The first thing I noticed was that the second profile was more neutral than the first one. The one made at the initial connection of the display was displaying colors quite a bit warmer than the second profile. The second thing I noticed in a ColorSync Utility comparison is that the second "warmed-up" profile had a slightly larger gamut in every direction.

In other words, as the monitor warmed up and the brightness of the backlights increased, the color of the display showed changed in cast slightly, and the overall gamut of colors that the display was able to represent increased.

Like exercise, calibration is good for you, but be sure to warm up first.


Michael Chen
2007-03-06 05:26:03
It been said you need at least half hour for CRT monitors
howmuch time do you need for the Apple LCD''s ?
2007-03-12 03:46:22
Wonderful advice!!!! Thanks so much. I am also interested in the answer to Michael Chen's question.