A THG Primer: CRT Guide

Color Temperatures

If you've played around with your monitor's on-screen display controls (OSD), you probably ran into a color temperature setting. Most monitors will let you adjust the color temperature (measured in kelvin) to one of three settings or more. The standard default settings are usually 9300 kelvin, 6500 kelvin, and 5500 or 5000 kelvin. 9300 kelvin is usually the default setting, and is sometimes referred to as "computer monitor white." This setting will give you the brightest picture, but is slightly bluish in color. 6500 kelvin provides a whiter white, sometimes referred to as "daylight white." People in the video world prefer this setting. The 5500 or 5000 kelvin setting is sometimes referred to as "paper white," and is commonly used in the print and prepress world. If you're doing a lot of desktop publishing or color printing then you might want to use this setting.

While some monitors will allow you to set your own temperatures or even play with the individual color values, you should probably avoid changing things too much, unless you have a specific purpose in mind and know what you are doing. For general computer use, you probably want to stick with the default 9300 kelvin setting.

Convergence Corrections

You should never have to adjust the convergence settings with a good monitor, but it's nice to know how, should the situation arise. As I mentioned earlier, convergence is probably the most important factor in producing the sharpest picture. Professionals use a convergence gauge to measure convergence errors, but DisplayMate has special screens that will show convergence errors.

You can also use the business card trick (showed to me by Jim Witkowski at Monitors Direct/Cornerstone). Put up a dark background with a thin, horizontal white line. Now, hold a business card up to the screen and slowly move it up, so that it crosses the line at a slight angle. If the monitor's vertical convergence is off, you'll see a red, green or blue fringe on the edge of the card. This trick also works for detecting horizontal convergence errors.