If it's the screen door effect, perhaps you are referring to the old projector TVs, because projection systems were more prone to door screen,effect, also known as fixed-pattern noise (FPN). But that effect isn't just horizontal lines, it also made up vertical and horizontal fine lines separating the pixels, which was kind of what I was referring to in my last post about pixel resolution. And this was something that plasma screens were touted to be better at eliminating years ago, but LCD and of course the newer LED technology has caught up to. But yes, I know what it is, and you can see it in any screen if you get close enough, but have never noticed it any worse in plasma TVs. I use to have an older projector that had it fairly pronounced, but it was only 640x480 resolution.