Some claimed that low refresh rate on screen caused it to flash. But that wasn't true, as long as the screen had slow enough phosphor. With older CRT displays i

Some claimed that low refresh rate on screen caused it to flash. But that wasn't true, as long as the screen had slow enough phosphor. With older CRT displays it was totally possible to read the text from the screen after three seconds of turning the display off or giving clear screen command. You could also play with magnets on the screen, not all screens got great degauss feature, so little magnet play was fun. It's also important to monitor that CRTs aren't equal. If you used regular 70s color TV it was very different from high end 21" Trinitron CRT used before flat panels became popular. Here you can see one nice CRT: https://www.youtube.com/watch?v=IweoaOb53XQ https://www.youtube.com/watch?v=IweoaOb53XQ One of the reasons why many computers didn't use 80 char line length was that TVs didn't produce sharp enough image and it was impossible to read 80 char lines. Of course it was also possible to modify displays to produce sharper image. With Spectravideo it was possible to use separate card to produce sharper image and 80 columns. http://www.samdal.com/SVIDOCS/STM-I_SVI806.pdf http://www.samdal.com/SVIDOCS/STM-I_SVI806.pdf