[old_tv_nut]

Originally Posted by Electronic M

...Col-R-Tel made a color wheel converter for monochrome NTSC sets. http://earlytelevision.org/col-r-tel.html
...

Did you ever stop to think how this could possibly work? It depended on the temporal characteristics of the human visual system. The field rate was so low that the pictures were guaranteed to flicker, yet you could see good color.

The reason is that the color temporal (flicker) response of the human visual system is much slower than the luminance temporal (flicker) response - that is, you could see that the luminance was changing due to the red to green to blue sequence, but you could not see that the color was changing in sequence, only the brightness variation. You only saw the blended color. So, the pictures were deemed viewable even though flickering strongly.

Some early advanced TV systems (leading up to HD) attempted to reduce the frame rate of the color component compared to the luma component. There were problems in fast moving objects with the color information jumping behind and/or ahead of the luma on sequential fields, which would have required some sort of motion compensation. Edit - but it was mostly unnoticeable.