Axiom Home Page Forums General Discussion The Water Cooler another quick question

What kind of resolution do regular tube tvs have? I have an old JVC 27", and was just staring at it and the question came to mind. Thanks.

I could be wrong, but I believe that all normal TV's are 640X480.

"normal" television resolution is 525 horizontal lines at 72dpi. I believe the image size of most broadcast material these days is 720x486 (a.k.a D1). DV is 640x480. The image size that can be viewed on the television is actually a few pixels less than 640x480. And just to throw this out, VHS is 320x240 - the same as mpeg1.

^billy

Thanks for the info. Learn something new everyday...

In reply to:

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I believe the image size of most broadcast material these days is 720x486 (a.k.a D1). DV is 640x480.

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Woo.. welcome to my world... students, place your books under your desks.

NTSC - North America - 720x486 D1 pixel aspect - 29.97fps "drop frame"
NTSC D1 pixels are slightly taller than wide (due to the way analog TV signals have been) at a ratio of 0.9:1... jokingly refered to in the biz as "Never The Same Colour". Frame Rate of 29.97 is refered to as "drop frame" (one frame is dropped from the time code every 10 minutes to make up for the time taken in V-blank - the vertical blanking interval, the time the electron gun takes to get back to the top of the tube to redraw)

PAL - Europe - 720x576 D1 pixel aspect - 25fps
PAL D1 pixels are off square at a ratio of 1.0666:1. PAL broadcasts reverse the phase on each alternating line, which corrects for phase problems - for the most part, colour is better in a PAL transmission. Ever wonder why Mad Max looked so skinny then you saw it played here? PAL pixels are fat, NTSC pixels are thin.

DV/DVCAM/DVCPRO - 720x480 D1 pixel aspect - 29.97fps "drop frame"
I only mention this because Squirrelyz mentioned it - it's a tape format, not a broadcast format.

Having said all that... a North American TV scans 525 lines (and there are really no horizontal "pixels" as such - the gun moves discretely down every other line and is turned on and off to paint phosphors as necessary)... and European TVs scan 625 lines.

... hope this helps - I could get more indepth if anyone cares.

Oh, and Squirrelyz - if you meet the person that started that nasty rumour about "72 dpi" being broadcast dot pitch, send them my way - that's probably the one biggest problem editors run into with marketing people - "I want my logo to be 2" high, so I sent my logo 150 pixels tall"... umm... 2" tall on a 13" screen or a 65" screen?

Bren R.

Damn, that is good stuff. I didn't think there were real pixels, but wasn't totally sure. So, then, why are the presentations so different from continent to continent? When everything supposedly goes digital, will things be more universal?

I have our marketing people send everything to the graphics department to be redrawn into vector artwork in Illustrator so I avoid explaining everything to the same guy 38 times...this is the same guy that always wants frame grabs of our stuff to use in print publications - and for years we've been trying to explain why that's a bad idea - you basically get a photo that's 720x486 at 72dpi. So while you are correct about the 72dpdi - it's a decent way of explaining to non-tv-pros how much detail NTSC SD television has and why 13" tv's look so much better than the big screens...of course with all the changes in televsion these days, this simplified explanation will change.
^billy