A Sharper Picture For The TI-99
The normal screen color of the TI-99/4A — assuming you have a color TV — is green while the program is running and blue when it is not. If you have a black-and-white TV, you can get a sharper picture by asking for a gray background with a statement like
10 CALL SCREEN(15)
at the beginning of the program. This disables the color-generating circuit of the TI-99 and removes the pattern of vertical lines often seen on a black-and-white TV that is fine-tuned for maximum sharpness. It also increases the sharpness of the characters. The change remains in effect as long as the program is running.
The same idea can be applied to other machines that allow you to control the background color.
Michael A. Covington