If you enjoy looking at photography online, you owe it to yourself and to the photographers you enjoy to determine proper gamma compensation for your monitor. If you're a photographer that publishes photographs online, you owe it to yourself and your viewers to perform gamma compensation for your monitor to ensure that what you see is what they will see and that all of your images are edited in a uniform fashion.
I'm not talking about full-on color calibration. While that is surely useful and a good idea if you want to see what you're going to get when printing, I'm only talking about color balance, and white and black point determination.
Without proper gamma correction, images may appear darker or lighter than the artist intended them to be. This means that, while the photographer may have intended the female figure to be entirely in silhouette, you see traces of facial features. Or that, when the artist intended for you to see the texture in the snow, you see nothing but a big white blob.
Gamma correcting your monitor is SIMPLE. First you need to "set a proper blackpoint":http://www.aim-dtp.net/aim/calibration/blackpoint/crt_brightness_and_contrast.htm. This step alone will make a huge difference. Secondly you use "this chart":http://www.normankoren.com/Gamma_black_new.png to determine the proper level of gamma compensation. For most Windows users it's 2.5, and for most Mac users it's 1.72 or 2.2. This is because Macs have built in hardware level gamma correction.
Of course, in order to adjust the gamma correction, you need software that does that for you. If you use Linux, xgamma will do the trick. Or, for something a bit easier to deal with try "monica":http://www.pcbypaul.com/linux/monica.html. Under Windows, you can try "QuickGamma":http://www.normankoren.com/makingfineprints1A.html#QuickGamma. Regardless of what tool you use, ignore the gamma value that they suggest you calibrate to. There is a lot of confusion regarding what you should be calibrated to. I suggest calibrating to 2.2, which is, supposedly, the proposed standard for sRGB images, which is what things are viewed in over the web.
Yes, there are people that claim that we should calibrate our monitors to achieve a linear gamma. And, there is some truth in this statement. By working in linear gamma space, we're able to preserve as much of the color space as possible. However, monitors have gone largely uncorrected for some time now. Working in linear mode will mean that you need to introduce a gamma of 2.2 (or 2.5, in some opinions, or 1.72 for macs) into the image or anyone operating outside of linear gamma will have a HORRIBLE image in front of them. Additionally, since all of the fonts, and graphics, and other images on the web have been created with any gamma compensation, and, therefore, anything but your own images will look TERRIBLE to you, and that's no good either.
Of course, ICC profiles are the REAL way to handle all of this. But, that's complicated. This is easy.
Just run the program and slide the things around until the chart evens out at 2.2, then go on your merry way. If EVERYONE does this, the web (and computer graphics in general) will look better and better. And, until everyone does, PC users will find OTHER images a little darker than usual, and Mac users will find them a bit lighter than usual. Of course, images edited on "compensated" system will look great to other compensated systems, and just the opposite on those that haven't bothered to compensate. It's a small price to pay.
