why can't I use a regular TV to color correct? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > The View: Video Display Hardware and Software

The View: Video Display Hardware and Software
Video Monitors and Media Players for field or studio use (all display technologies).


Reply
 
Thread Tools Search this Thread
Old February 16th, 2005, 01:37 PM   #1
Regular Crew
 
Join Date: Apr 2004
Location: S.F., California
Posts: 61
why can't I use a regular TV to color correct?

I know that a regular TV has all sorts of unique variations, defecincies and whatnot that'll make it different than every other TV, but at the moment I can't afford a NTSC monitor. So I've been using my LCD computer screen to color correct, and I get a look I'm happy with. Then I project it on a TV or whatnot and see that the contrast is way too harsh, the colors way too saturated, everything looks too harsh and drastic compared to the image i thought i originally had. So i'm thinking of color correcting with a crappy $80, 12" TV screen. at least I'll get something closer to what I want, right? or am i just gonna screw myself over somehow? can i get acceptable results using a TV until I can afford a monitor?

and finally, if i were to use a regular TV, how would i go about (roughly) calibrating it? thanks!
Allen Nash is offline   Reply With Quote
Old February 16th, 2005, 02:20 PM   #2
Major Player
 
Join Date: Apr 2004
Location: Los Angeles, USA
Posts: 539
Because...if you correct it for your TV, it won't look good on another. TV's vary very much in how they show color.

If you use a properly calibrated NTSC monitor, the show will be set up for standard colors. If your project is going to be broadcast on TV, then the monitor is the only way to go. Well...darn it, I'm a purist...I think if it is going to be any high end pro thing, like DVD or anything other than a wedding or dance recital you need that monitor.
Shane Ross is offline   Reply With Quote
Old February 16th, 2005, 02:42 PM   #3
Inner Circle
 
Join Date: Sep 2002
Location: San Mateo, CA
Posts: 3,840
Shane is correct, in that if you want standard colors, you should use the industry standard monitor. Barring that, if all you have is an ntsc television set, at the VERY least, set up the bars correctly on it.
Richard Alvarez is offline   Reply With Quote
Old February 16th, 2005, 03:26 PM   #4
Major Player
 
Join Date: Jan 2005
Location: Beaverton, Oregon
Posts: 399
Hopefully this isn't too off topic or hijacking....Any recommendations on an "affordable" monitor for this purpose? Also, where can I learn how to color correct?

Thanks,
Scott
Scott Shama is offline   Reply With Quote
Old February 16th, 2005, 04:27 PM   #5
Regular Crew
 
Join Date: Apr 2004
Location: S.F., California
Posts: 61
Any recommended books on color correcting? My NLE's documentation is basic and it always feels like i do more harm than good whenever i try color correcting.
Allen Nash is offline   Reply With Quote
Old February 16th, 2005, 04:35 PM   #6
Inner Circle
 
Join Date: Jun 2003
Location: Toronto, Canada
Posts: 4,750
Really stupid way of calibrating a normal TV:
Go into the menu and set all the picture settings to its middle values. Most monitors are factory set to give extremely contrasty, bright, saturated colors.

The videouniversity instructions are better, but you need that filter. Even then, your monitor may have deficiencies that cannot be compensated for.

Quote:
Any recommendations on an "affordable" monitor for this purpose?
If you want to learn just the artistic side to color correction, then just any monitor will do basically. The same principles apply whether you have just any monitor or a NTSC monitor costing thousands of dollars.

It may be helpful to have a CRT of some sort with adjustable white point. If you use a computer monitor, get a CRT with adjustable RGB so you can make whites look white (without a slight color cast).

If you want to do a proper job then you'll need a good monitor and that costs money. You may also need an EXTERNAL waveform monitor to check proper levels.

Quote:
So i'm thinking of color correcting with a crappy $80, 12" TV screen. at least I'll get something closer to what I want, right? or am i just gonna screw myself over somehow?
1- Hook up just any TV to your editing system. Computer monitors do not show what your image looks like for many reasons. Having just any TV will be a huge improvement, although the TV may not give very good color accuracy.
2- I noticed that certain TV/monitors really brighten your image and make underexposed footage look way better than it does. I don't know if this is the case with all consumer stuff. On some other sets, underexposed footage will not look so great.
Glenn Chan is offline   Reply With Quote
Old February 17th, 2005, 09:24 AM   #7
Regular Crew
 
Join Date: Sep 2003
Location: Quebec, QC, Canada
Posts: 123
... And don't forget that the black level of your DV footage is set at 0 IRE, but you have to push it up to 7,5 IRE for a North-American NTSC TV or monitor. That's part of the reason why our DV picture is too dark when viewed on a standard TV directly from the camcorder's A/V out.

For lenghty explanations, search this forum for "setup". It has been discussed frequently.

Easy way out: transfer your final footage onto a DVD. All Home DVD players sold in America automatically add the 7,5 setup through their A/V outputs for correct video level on a TV screen.
__________________
Norm :)
Norm Couture is offline   Reply With Quote
Old February 18th, 2005, 11:01 AM   #8
Major Player
 
Join Date: Sep 2004
Location: Maryland, USA
Posts: 382
I do all of my color correction on a few regular 13-19" TVs purchased from Walmart. I've got a scope as well as a broadcast monitor at my disposal, but I just don't use them. I have in the past, and while things will look stellar on that gear, it looks meh on the average stuff that the viewers, clients, basically everything everyone other than me will be using.

Develop for your target, not just to the spec. I trust my eyes and ears (and I've got good eyes and ears) for a lot of stuff where there would otherwise be discrepancy.


PS, $.02 ;-)
Patrick Jenkins is offline   Reply With Quote
Old March 2nd, 2005, 02:37 PM   #9
Regular Crew
 
Join Date: Apr 2004
Location: S.F., California
Posts: 61
thanks for all the replies, guys. some more questions:

1) how would i follow the calibration instructions on my cheap TV if it doesn't have the blue gun mode? Are there some already blue-gunned images i can DL and use?

2) how do i add 7.5 IRE? Is this an adjustment i can make in Sony Vegas, perhaps in a track filter? I don't have a DVD-burner so can't use that.

3) Actually I have footage shot on my DVXa which I can't remember if I added the 7.5 to or not (it's an option on the DVX). Is there a way to find out now?

4) ...Any good color correction books? I'd like to learn the nitty-gritty of what settings, filters, etc. do and how best to use them. Or does everyone just eyeball this stuff?


thanks :)
Allen Nash is offline   Reply With Quote
Old March 2nd, 2005, 07:19 PM   #10
Regular Crew
 
Join Date: Sep 2003
Location: Quebec, QC, Canada
Posts: 123
Allen,
As long as you work in a digital environment, you should leave the black level at 0 IRE. That is on the cam when you shoot, and on the computer when you edit. Make a 0 black-level master document that you can always re-edit for a correction.
The only moment you need to raise the black level to 7.5 IRE is when you transfer back into the analog world, such as making a VHS copy or playing back on a NTSC TV screen from your camcorder's A/V output.
__________________
Norm :)
Norm Couture is offline   Reply With Quote
Old March 2nd, 2005, 07:59 PM   #11
Inner Circle
 
Join Date: Jun 2003
Location: Toronto, Canada
Posts: 4,750
Quote:
1) how would i follow the calibration instructions on my cheap TV if it doesn't have the blue gun mode? Are there some already blue-gunned images i can DL and use?
Read the instructions at http://www.videouniversity.com/tvbars2.htm again- it tells you to use a blue gel. I'm not sure if using a blue gel will actually give you that good results... but it might be the best you can do. Or you can try eyeballing things too. Consumer TVs can be really wacky anyways, so it may not make that big of a difference.

More calibration notes:

First, set color temperature on your TV to 6500k if possible and go through the videouniversity instructions.

The next step is to try to make your computer monitors the same color temperature between your computer monitors and your TV or NTSC monitor. This way your eye's white balance won't shift because of your computer monitors.

In your computer monitors, go into its controls and look for color balance/temperature/RGB controls. Ideally it will have RGB controls. Generate a white image (235, 235, 235 in digital values, where 255 255 255 is the whitest white) and display it on all your computer monitors. Check your scopes in your NLE to check that this white is 100(IRE). In Final Cut, be *especially* sure (the numbers you put it do not necessarily correlate to the actual 8-bit values). The goal of this is to display white on your all your monitors, but not the illegal white. Adjust the brightness and contrast settings on your computer monitor loosely to try to match brightness.

Now change the image to completely green (0, 235, 0). Try to match brightness on your computer monitors to your TV/NTSC monitor. Hopefully this gets the monitor close in terms of brightness. Now go and change the image back to white again. Go into the RGB controls for your monitor (*not all computer monitors have them, but most do). Adjust the controls for the red and blue gain/guns until whites are white on all monitors (without any tint of orange, blue, etc.). If a monitor is too cyan-ish, increase red and blue. If a monitor is too magenta-ish, decrease red and blue.

An alternate method is to display red or blue and then try to match brightness across all monitors. You might find this easier.

Be aware that your eye constantly adjusts its white balance, so if you stare at a monitor long enough it will become white.

Once done calibrating:

See how far off your monitor is. Have your room setup the way you normally would when color correcting. If the color temperatures in your room are inconsistent (chances are they are), then you can try turning off all lights except for what you need: computer monitors and your TV/NTSC monitor. If you have windows, work at night or pull the blinds/drapes/curtains over it.

Display white (235 235 235) on all your monitors. If the monitors do not look exactly white, take a note of it.

Take some real images and turn them into grayscale. You can use the black and white effect in your NLE, or the color correction or HSL controls set to desaturate. All the grays should appear gray without any color tint. Chances are this isn't the case. Take note of how far your monitors are off.

Next step is to run a gradient through your monitor and check that you can see a gradual gradient (color transition) from 16 16 16 to 235 235 235. From 235 235 235 to 255 255 255 white, it shouldn't really matter that much if you can see a gradient. From 16 16 16 to 0 0 0, you shouldn't see a gradient on your TV/NTSC monitor. Take note of how the gradient appears on all your monitors.

If your NLE has a curves or gamma control (gamma is usually found in color correction filters), put it onto the gradient and push it to extremes. You will emulate what the gradient will look like if your monitor is whacked. If changing the gamma response of your monitor makes things look better, take note of that and you will know that your monitor is a little off. Old monitors especially suffer from low gamma... if so, boosting gamma in your NLE will make the gradient look better with smooth transitions from end to end.
Glenn Chan is offline   Reply With Quote
Old March 3rd, 2005, 08:21 AM   #12
Major Player
 
Join Date: Jun 2004
Location: McLean, VA United States
Posts: 749
In the Mac world if you calibrate your monitor (using a "spider", i.e. a spectrophotometer which mounts temporarily to the screen) made by Gretag, Monaco or other manufacturers) and be sure to use the profile generated when using the NLE then what you see on your monitor should be pretty darn close to what you'll see on a production monitor (though not exactly). I am assuming that Apple, a plank holder in the ICC, is smart enough to know that video in the USA is shot in NTSC space, map that into a working space for manipulation and then transform the working space images through the monitor profile before displaying the video (and transforming back to NTSC for palout through Firewire to the studio monitor. These transformations handle color shift and gamma issues both.

I mention Macs because that's what I know. The PCs generally eventually catch up though proper handling of ICC profiles was quite a long time coming.

Given this, get your stuff looking nice on the studio monitor and/or your computer monitor properly profiled and then play it back on a TV and it will look blue all over because TV sets are sold with a 9300K white point setting. Play it on a different TV and the colors will be all over the map. I often wonder if we shouldn't make our videos yellowish on the calibrated devices to try to compensate for this 9300K business. There is no way to handle the variability between sets with respect to gamut though.
A. J. deLange is offline   Reply With Quote
Old March 3rd, 2005, 02:03 PM   #13
Inner Circle
 
Join Date: Jun 2003
Location: Toronto, Canada
Posts: 4,750
Quote:
Given this, get your stuff looking nice on the studio monitor and/or your computer monitor properly profiled and then play it back on a TV and it will look blue all over because TV sets are sold with a 9300K white point setting. Play it on a different TV and the colors will be all over the map. I often wonder if we shouldn't make our videos yellowish on the calibrated devices to try to compensate for this 9300K business. There is no way to handle the variability between sets with respect to gamut though.
It won't look blue since your eye will adjust itself to whatever color temperature the television is. Leave whites as white. On consumer TVs with really cool color temperature, those whites will look white (and not blue-ish).
Glenn Chan is offline   Reply With Quote
Old March 3rd, 2005, 04:13 PM   #14
Major Player
 
Join Date: Jun 2004
Location: McLean, VA United States
Posts: 749
That's probably true of you are in a darkened room but during daytime or with the lights on where you can see normally balanced stuff around the screen, it looks blue! Now it may be that it looks bluer to me than the average consumer because I know it's set for 9300K and he doesn't. And I am not seriously suggesting that people edit towards yellow to compensate. Most of the video I see I'm watching on my calibrated computer screen and that looks just great to me.
A. J. deLange is offline   Reply With Quote
Old March 4th, 2005, 08:19 AM   #15
Major Player
 
Join Date: Feb 2005
Location: Rochester, NY
Posts: 263
<<<-- Originally posted by Glenn Chan : Read the instructions at http://www.videouniversity.com/tvbars2.htm again- it tells you to use a blue gel. I'm not sure if using a blue gel will actually give you that good results... but it might be the best you can do. -->>>

Hello,

Anyone know a good source for this gel??

Thanks :-)
__________________
AM
Anthony Marotti 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 > The View: Video Display Hardware and Software

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 10:56 AM.


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