Red afterglow
 

I have been noticing a really odd effect on my TV. I have noticed that if I have a color bar pattern on the TV, and cut directly to a black screen, the black level has a slight reddish tint to it, but after about 20 seconds it goes back to a neutral grayish black.

Is this an optical illusion, or can there be something electrical causing this freaky effect?

Screen phosphors can have different persistance rates. After running the red hard and then suddenly cutting off some "afterglow" can occur. Perfectly normal.