What are underscan & bluecheck ? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Open DV Discussion
For topics which don't fit into any of the other categories.


Reply
 
Thread Tools Search this Thread
Old April 6th, 2004, 01:05 PM   #1
Regular Crew
 
Join Date: Feb 2004
Location: Belgrade, Serbia
Posts: 38
What are underscan & bluecheck ?

Regards,
I am looking to buy video monitor, some models have these features and same have not. Can someone explain to me what are underscan and blue check for, sorry but I am totally new to this.

Thanx a lot
Darko
Darko Tomic is offline   Reply With Quote
Old April 6th, 2004, 01:11 PM   #2
Regular Crew
 
Join Date: Oct 2002
Location: Cambridge, UK
Posts: 164
Underscan - a CRT TV does not display 100% of the video frame, but cuts off a small percentage on all sides. Underscan setting on a PAL monitor means you can tell the monitor to display 100% of the image - it does it by reducing the image size a little.

Blue check - turns off all guns except the blue gun. This is used together with colour bars to adjust the PAL monitor's settings - colour bars consist of colurs that should appear alternately black and blue when viewed with blue gun only, and any imbalance between the brightness of the blue bars can be adjusted.

Julian
Julian Luttrell is offline   Reply With Quote
Old April 6th, 2004, 01:18 PM   #3
Contributor
 
Join Date: Jan 2003
Location: Kansas City, MO
Posts: 4,449
If you're going to shell out money for a decent monitor, be sure to get one with underscan and bluecheck. Bluecheck is sort of a misnomer anymore, since lots of Sony monitors now turn the bars white instead of blue, but the same principle works--you adjust till the bars match properly and you're cool.

Underscan is also more important today than in the past because lots of things get released on CD for playback on computers, or for video projection. In these cases there is no monitor crop. Professional cameras all give you underscan in your viewfinder, but some "prosumer" cameras do not. If you're shooting something that's critical and don't have any means of viewing the entire frame, you could run into a problem down the line.

If you're looking at the Sony portable 8" field monitors, you may have noticed that one is a few hundred bucks more than the other. The more expensive one is a higher resolution monitor. Until a couple of years ago I used a larger 10" Panasonic field monitor that had fairly low resolution, but it was OK for my purposes. When I bought the new Sony (because I needed a 16:9 monitor), I paid more for the high res because of the smaller screen. And it's even smaller when monitoring 16:9 in underscan. The higher resolution is worth the money in the smaller screen sizes.
Bill Pryor is offline   Reply With Quote
Old April 7th, 2004, 02:12 AM   #4
Regular Crew
 
Join Date: Feb 2004
Location: Belgrade, Serbia
Posts: 38
Thanx for detailed explanations, Julian and Bill.
Ok, I ll get one with underscan and blue check functions ...
Now I have to decide do I need high resolution monitor or not. Some models have more than 550 lines, and most new JVC models have more than 750 horizontal lines. If I use this monitor only for PAL broadcast, I dont need high resolution monitor, tell me if I am wrong. The resolution is 720x576, ie this is 576 horizontal lines overscan, right ??

Thank you
Darko
Darko Tomic is offline   Reply With Quote
Old April 7th, 2004, 02:20 AM   #5
RED Code Chef
 
Join Date: Oct 2001
Location: Holland
Posts: 12,514
It seems like some of you guys might know a thing or two about
PAL monitor calibration. I've looked everywhere, but every calibration
test I could find a year or so ago was for NTSC monitor calibration.
The PAL colour bars are also different from the NTSC ones.

So does anyone have or know of a good source for PAL monitor
calibration with the PAL bars? I mean something I can print out
and keep for reference? Again, there are numerous guides for
NTSC and I would like to have one for PAL as well. Even if it is
very simple for example.

Thanks.
__________________

Rob Lohman, visuar@iname.com
DV Info Wrangler & RED Code Chef

Join the DV Challenge | Lady X

Search DVinfo.net for quick answers | Buy from the best: DVinfo.net sponsors
Rob Lohman is offline   Reply With Quote
Old April 7th, 2004, 03:49 PM   #6
Regular Crew
 
Join Date: Oct 2002
Location: Cambridge, UK
Posts: 164
Rob,

very good question! I have never been 100% confident about getting black level correctly in PAL, but do the following:

I first adjust black level using brightness control, getting it as low as possible but still seeing a change as I adjust.

Then I adjust white level using contrast so that white is as high as possible without blowing out and still shows some change when I adjust the contrast.

Then I adjust colour using chroma (blue check on) so that left and right blue bars are the same brightness.

This will work with both 75% and 100% bars (I think).

As you so rightly imply, the pluge bars (3 dark greys) in an NTSC colour bar have no place in a PAL one - but this does make it tricky to adjust black!

Regards,

Julian
Julian Luttrell is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 01:39 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network