The LCD panels that Apple incorporates into the iMac and MacBook computers have become increasingly brighter as flat-panel technologies advance, with the latest panels being some of the brightest on the market. In some models or configurations; however, even at the lowest setting the display appears too bright for people.
"My display, when turned to its absolute lowest possible brightness setting is still extremely bright. More so than any of the other iMacs and MacBooks that I've owned. I was wondering if anyone knew how to change the brightness setting even lower by some way I'm not aware of. It's to the point where at night when the brightness is at its lowest, I can't stay in front of the computer for very long. It's blinding."
In addition to the 24-inch iMac having this problem, owners of the 20-inch model have noted this issue as well. While the monitors may be bright at their maximum settings, the display dimming should show a substantial gradient and should be able to match the ambient levels of even very dimly lit rooms. If you are not able to see much of a change between the minimum and maximum brightness settings, there are a couple of things you can try; however, if these do not work, then we recommend you contact Apple about the problem since it may be a hardware malfunction.
1. Calibrate the monitor
Many times the computer may be using an incorrect color profile for the screen. Various applications can sometimes incorrectly set the display color profile (screensavers have been known to do this), and if a generic one is used, the colors can appear washed out or otherwise imbalanced. The first thing to do if your monitor appears washed out is to try a few different color profiles. These are available in the "Displays" system preferences by clicking the "Color" tab. Selecting a display profile above the horizontal line in the profile list should put the monitor colors at a level suited for the monitor. If this works and the colors are less washed out, we recommend calibrating the monitor so the colors are as even as possible for your display. To do this, click the Calibrate button to generate a custom profile for your monitor.
In the calibration utility, we strongly recommend running in Expert mode, and taking the time to accurately match up the patterns on the screen. You will be given a series of Apple logos in boxes, and you will need to change both the color and brightness so the logos fade into the background. If you take your time and ensure the Apple logos are absolutely invisible for each step in the calibration, your colors will look far richer and crisper than when using the generic profiles that come with the computer. One recommendation is to also try third-party calibration utilities such as SuperCal (http://www.bergdesign.com/supercal/). Many people have found the built-in calibration utility to be rather cumbersome and not as thorough as third-party solutions.
2. Standard fixes
Before trying other fixes, first try booting off your OS X installation DVD. This will load standard color profiles, and if the display is still washed out then it suggests a hardware setting is to blame. At this point, try resetting the computer's PRAM, which contains some display settings. Otherwise, if the display appears normal when booted off the installation DVD, boot into safe mode by holding the shift key at start-up and then run a permissions fix using Disk Utility. Additionally, if you have third-party system maintenance utilities, try running them to clear out caches and other temporary files, as well as run various maintenance scripts on the system. When all the scripts have been run, reboot the system and try calibrating the monitor.
1. Use third-party "dimming" applications.
If calibration doesn't work and you are unable to take your computer in for servicing, running a screen "dimming" application may help. These applications create a custom monitor profile that keeps the calibrated color balance the same but prevents the pixels from allowing too much light through, thereby decreasing the brightness without changing the overall backlight brightness. Several people with extremely bright displays have found the following "dimming" utilities to help: