Monitor calibration is very essential for seeing true colors in a photograph (or any other multimedia usage). It is the first step in setting up a photo editing workstation. If the monitor is not calibrated, then a photo may appear too bright or too dark or the colors may be improperly saturated. When that photo is printed, the difference will be far more obvious.
Monitor calibration can be done by software or by hardware devices that sync between the display and the printer. For a quick usable calibration, the brightness and contrast settings of the video card is sufficient (monitors also have these settings, but modifyng them does not necessary “calibrate” it). To perform calibration by simply changing the settings through video card control panel, one needs a test image. Below is a pretty good calibration test image by Photo Friday:
If you are on Linux and do not have a video card (i.e. all you have is Intel GMA etc.), then you can tweak gamma using this command from terminal:
Linux-user # xgamma -gamma 0.8
where 0.8 corresponds to 80% gamma.
To adjust brightness, you can either use the function keys on your laptop (if you are lucky enough that they work for your machine and OS combination – mine doesn’t work) or run the following script from terminal (save as brightness.sh for example):
#usage: Linux-user #./brightness.sh 0.5 (i.e. for 50% brightness)
xrandr --output LVDS1 --brightness $1
For a more detailed calibration and technical overview, the following article is very useful:
Monitor Calibration and Gamma (by Norman Koren).
It is crucial that the monitor/ display is calibrated before an image taken with a digital camera is edited on it – as otherwise the editing will not look proper on standardized (i.e. calibrated) displays, nor would it print as expected (although to ensure the latter, calibration procedures would go beyond the simple slider settings of a video card).