How much of a problem is burn-in on standard picture-tube TVs?
“Burn in” is really a misnomer – nothing is burned. Intense use of certain portions of the screen leads to weaker light output – later, when the screen is displaying a neutral color, you see the shadowy still image of what was there – the weakened phosphors appear darker. If you pause a DVD movie on a scene with bright areas, and leave it that way for a long-enough period, you will potentially see some shadowing. Susceptibility to burn-in depends on many factors, including image content, brightness, contrast, and length of time an image is displayed, plus the TV’s phosphor characteristics. TV programs generally don’t contain any bright image fixed on one position where it might cause burn-in. The constant change in brightness across the screen tends to even out the phosphors. So burn-in is not too big a problem, most times. Conventional analog TVs have generally become quite robust, mostly due to improvements in phosphor design.
