Ask Tim Grey Guest Post – Display Brightness

Today’s Question:

I cannot adjust display luminosity on my 2009 iMac 24″ display. I have the EyeOne Display2 package, but am told I can only set Kelvin and luminosity on an iMac. Calibration says display is at 170 but needs to go to 120. Brightness control slider can’t go darker then 170. Called Apple and they had no solution, and tech support said they are not given native luminosity settings for their displays.

Tim’s Answer:

The issue of high luminance values for LCD displays is actually a very common one. Specifically, most LCD displays are way too bright out of the box, and need to be dimmed in order to ensure accurate results in the context of a color-managed workflow. In some ways this is a good thing, since it means that over time as the LCD illumination starts to fade, there will still be adequate overhead to ensure accurate brightness. Of course, from a color management point of view it can be a problem, particularly if you’re not able to adjust the monitor display downward in luminance to an acceptable target value (around 100 to 120 candelas per square meter).

Unfortunately, many LCD displays lack an adjustment for contrast (or brightness) at all, and some of those that do aren’t able to get the luminance value down far enough. It seems monitor manufacturers are more interested in producing a bright, vibrant display than on ensuring an accurate display of photographic images. If your display doesn’t offer an adequate control to reduce luminance, you may be stuck with a display that is too bright. Being aware of this, you could be careful about the adjustments you apply (making things a little brighter than they should be, for example), but this is far from ideal. Making an image appear “wrong” on the display so it will appear correctly elsewhere is difficult and often problematic.

Fortunately, there are some solutions available. Obviously you could purchase a different display (except for the fact that in the case of the photographer posing this question, the display is an integrated part of the overall computer in the case of the iMac). But there are also some software solutions available. One of the most promising (though a solution I’ve not yet had an opportunity to test myself) is ColorEyes Display Pro from Integrated Color Corporation. This software integrates with existing colorimeters (including the EyeOne Display2 I recommend), and enables you to adjust the brightness of the display to the target luminance value you’re looking for. By all accounts this looks like a great solution, and I’ll be testing it out myself in the near future.

You can download a trial version of the software through the Integrated Color website here:

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Author: Red River Paper

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