![Smile :)](./images/smilies/icon_smile.gif)
Gamma is effectively the transfer characteristic of light and shade, and can be anything from a straight-line graph to one more of a logarithmic nature - which suits human eyes better.
When I worked in TV broadcasting, back in the days of black-and-white TV - ie pre 1975 in Australia - monitor calibration was always a problem for around the station compatibility. Since colour arrived, it has got worse.
Monitor calibration in theory comprises setting black level (level at which the CRT gun shuts off its electron stream), and peak white level (a fully saturated mix of all three colours) which cannot get any brighter, since colour came in the various red, green and blue levels.
In monochrome TV days, a light meter was used to read that CRT emissions of white, black and the intermediate levels, and brightness control used to set black level, and contrast peak white.
Hence the colour bars signal at the head of a program tape, which include black and white references, meaning once the monitor is set correctly, the program will appear optically as the producers intended it should.
In the domestic environment, since adjustments are now available to the end user by menus on screen and buttons to tweak, it seems more than likely it's just about impossible to assume any user has not maladjusted the settings.
I created a set of "test signal" computer images for anyone who wanted to use them during the time I was writing for Echo Magazines in Brisbane in the late 1980s and all the 1990s. They were created at a resolution of 800x600 pixels because the 625-line/50 fields/second television signal approximates to slightly less than that. Which, of course, is why the Macintosh has an unusual optional resolution there
![Smile :)](./images/smilies/icon_smile.gif)
I came across them again after our move here in 2002, and posted them to one of my virtual hosts on an apache web server at http://micro-hard.homelinux.net/wallpap ... /index.htm
![Image](http://micro-hard.homelinux.net/wallpapers/setup_wallpapers/320x240/bars.jpg)
![Image](http://micro-hard.homelinux.net/wallpapers/setup_wallpapers/320x240/4x3_screen.jpg)