What are underscan & bluecheck ?

[Darko Tomic]

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

[Julian Luttrell]

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

[Bill Pryor]

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.

[Darko Tomic]

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

[Rob Lohman]

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.

[Julian Luttrell]

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