are you refering to a trail of pixels or false artifacts? That is usually caused by high speed movements along with an interlaced broadcast such as 1080i.
Fixed pixel tv's such as plasma and lcd have to deinterlace the picture and then show it as a progressive picture. The time it takes for the tv to do this can create a lag or blotching that I believe you were refering to.
hope that helps
I've been trying to find more information on both and it seems I keep ending up with nothing. Just want a better explanation of why blotching occurs, and what all an ISF calbration entails on lcd and dlp projections as well as lcd and plasma flat panels.

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