Notes on monitors, flat panels and pictures
The images may look very different on different computer monitors or flat panels due to big variations in display parameters. I was very surprised how different my pictures looked on different computers, on some they looked OK, but on many they looked very bright and with visible pixel patterns, or dark with many details missing.
Nowadays flat panels (LCD) rule, but even within their population the
differences are big. Setting up optimal parameters for a monitor/LCD and graphic
card is very important if you want fully enjoy web based multimedia.
Unfortunately astro images are especially sensitive to these settings ...
When the brightness range is properly set the brightness distribution needs
to be adjusted by choosing and applying appropriate gamma correction.
There are several good pages explaining gamma and its calibration,
I personally like best "The
Monitor calibration and Gamma assessment page" at Photoscientia web site and "Monitor
calibration and gamma" by Norman Koren. You need a program to
apply the gamma adjustment to your graphic card, many cards have such
options in their control programs: AMD Catalyst has gamma settings under
"Monitor Color", and so does nVidia in its Control Panel. You can also use
QuickGamma on Windows, there is a tool for Linux called Monica
that I used,
and beside this two there is also a multitude of other tools either commercial (Adobe ships one with
Photoshop) or free. The gamma calibrating images that are the easiest to use
IMHO are the ones from Photoscientia web site, you need to adjust gamma to make the image as color
neutral as possible in all brightness version for the given gamma value. Below are several calibrating image
sets (3 for each gamma value: dark, medium and bright, copied from
Photoscientia web site), spanning gamma
from 1.8 to 2.4. My pictures (and most multimedia on the Internet) are optimized to be displayed with gamma=2.2.
Make sure all the adjustments are done with well warmed-up monitor or LCD and in
the room that is properly lighted - especially gamma adjustments are sensitive
to lighting levels. QuickGamma provides its own calibrating image, but somehow I
found it more difficult to dial in - but of course it may be different for you. There is also
a Java applet that allows to estimate current gamma correction at
various brightness levels.
I strongly recommend to spend a few minutes adjusting your monitor and graphics card, it is indeed well spent few minutes! Your multimedia experience will be much better, not only on this site, but anywhere in the Internet.