CBS still looks like the geriatric channel to me...

I haven't watched enough high definition TV to notice if this phenomenon still exists, but have you ever noticed that the big networks always seem to look just a little different than each other? CBS always looks kind of pale. ABC looks a bit different. NBC kind of has this brighter quality to it. Leave it to Chuck Klosterman in his monthly Esquire column to get to the bottom of this:

I have always wondered this: Why am I able to see any random television program, often for less than ten seconds, and immediately recognize which network the show is airing on? To me, the differences seem obvious and undeniable: On ABC, colors are always darker and the definition is softer. NBC programs look more like traditional videotape (brighter, sharper, more aggressively modern). Everything on CBS has a slightly grainy, understated appearance. Fox looks like the middle ground between CBS and NBC. When the show Cavemen premiered last fall and I came across the first episode by accident, I did not know what channel I was watching, but I did know this: Aesthetically, Cavemen looked like an ABC show. It looked like Head of the Class, which had looked like Barney Miller. I had a similar experience when I first saw 30 Rock, a sitcom that visually resembles Friends (which visually resembled Silver Spoons). These relationships have nothing to do with content; they refer only to the technical, non-narrative aspects of how the shows are broadcast. For reasons I don’t understand, I can identify the look of any major network instantaneously. So can a lot of other people. We can do it without even trying.

Except that we can’t.

Read the rest of the article here if you're intrigued, although I still don't think he quite answers the question.  Each network's broadcast does look different, as you can always tell when they air the State of the Union Address or some other common live feed.