Abstract: An electronic filter system for electronically placing a filter on the screen of a video display monitor. A video signal after prescribed processing is fed into an arrangement of four switches. The first switch is operatively connected to three transistors, and through the second, third and fourth switches, to three potentiometers. When the various transistors conduct, they each produce an output signal that is fed to the input of a conventional color video display monitor having three primary color guns. The signals from the three transistors are fed to each of the primary color guns in order to produce varying images on the display monitor. The second, third and fourth switches provide a convenient way for selectively controlling the activation of the green, red and blue guns of the display monitor. Several different sources of video signals for introduction into the inventive circuitry are contemplated.