why can't I use a regular TV to color correct?

Bill Keen · March 7th, 2005, 06:32 PM

<<<-- Originally posted by Anthony Marotti : <<<-- 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 :-) -->>>

I'd like to know this too.... part # at B&H perhaps? Thanks.

Glenn Chan · March 8th, 2005, 01:55 AM

If you get a filter sample pack, you might get enough blue gels to get it strong enough that it cuts out everything but blue. For example, I have a swatch booklet from Lee Filters. If you pull out all the "blue" filters and then double them over once, that's strong enough.

If you have several samples then things may or may not get easier.

CAVEAT1: It gets really dark. You will have to cup your hand over your eye nicely and wait for your eye to adjust for the darkness, or make some sort of screen/mask which shows relevant sections of NTSC bars or tone.

I haven't

CAVEAT2: I don't know if it's any better than eyeballing it, although I suspect eyeballing it is better. Just fiddle around with the hue control until you know what the wrong setting looks like, then fiddle around with it some more to remove color impurities. Then run an image with accurate flesh tones through it to make sure things look like. If you get flesh tones right you are in pretty good shape. (They might also be the hardest).

A blue gel may not pass the right wavelengths of light to let you do things accurately. Plus, if flesh tones look right to your eye then you're in pretty good shape (while the gel method may not do that).

Other methods:

B&H lists the wratten 47B filter:
http://www.bhphotovideo.com/bnh/cont...u=26457&is=REG
All I can say is: Expensive!!! (probably extreme mark-ups.) The 14X18" filter is $863.95...
The 3X3" is $55.95

Not worth it IMO.

Some color correction books also come with a gel for you to calibrate your monitor.

Chris Byrnes · March 16th, 2005, 10:44 PM

Consider the possibility of properly calibrating your computer monitor. DVRack from Serious Magic contains the code, switchws and instructions for doing this. This is just a minor function of the product, but very quick and useful In fact, they have a light version of the product that will do this for less money than any solution above other than gels on an already owned TV. And you can download the product from their site to try it out for 30 days. If you deice you want full function of the product on a laptop (the environment it was really designed for) then their license and activation allow you to install and run the product on two computers - so you can use full function on the laptop and just use it for calibration and monitoring on your editing system. If you are not familiar with the product it provides a full set of scopes via software emulation and captures firewire from your cam directly to disk. The sureshot function is incredible for perfecting your cam settings after the display is properly calibrated.

I have no relation to SM or any of its distributors. I am just an enthusiastic user.

Glenn Chan · March 17th, 2005, 11:00 PM

I think using a television is still a much better idea than DVRack or any other computer monitor-based solution.

Why:
1- Unless you use a hardware spectrometer/calibration device along the lines of a Colorvision Spyder, a computer monitor will still experience the same amount of color shift as a television.
2- Computer monitors use different phosphors? I noticed that pure green on a computer monitor does not match the green given off by a Commodore monitor (which isn't exactly a TV), but nonetheless color reproduction is different between various monitors.
3- A computer monitor will not show interlacing, chroma crawl artifacts, underscan, or bleeding/flaring.
(4- CRTs tend to be more color accurate than LCDs. Of course you can get CRT computer monitors.)

Anthony Marotti · March 18th, 2005, 10:26 AM

Plus... How many of us really want to lug around and extra piece of gear, especially when it isn't going to be as good as an NTSC monitor, and can only add another level of possible problems to your shoot ???

Scott Shama · March 18th, 2005, 04:44 PM

Hey Glen,

You mentioned Color Correction books...care to recommend any? I just bought my first NTSC monitor and I want to learn how to utilize it properly. I also want to learn when I need to put color bars on my tape. Is it everytime I shoot with different lighting or just at the begining of each tape?

Sorry if that sounds like a basic question, I am just learning the technical side.

Thanks,
Scott

March 18th, 2005, 10:26 AM	#20
Anthony Marotti Major Player Join Date: Feb 2005 Location: Rochester, NY Posts: 263	Plus... How many of us really want to lug around and extra piece of gear, especially when it isn't going to be as good as an NTSC monitor, and can only add another level of possible problems to your shoot ??? __________________ AM

March 18th, 2005, 04:44 PM	#21
Scott Shama Major Player Join Date: Jan 2005 Location: Beaverton, Oregon Posts: 399	Color Correction books...? Hey Glen, You mentioned Color Correction books...care to recommend any? I just bought my first NTSC monitor and I want to learn how to utilize it properly. I also want to learn when I need to put color bars on my tape. Is it everytime I shoot with different lighting or just at the begining of each tape? Sorry if that sounds like a basic question, I am just learning the technical side. Thanks, Scott

March 7th, 2005, 06:32 PM	#16
Bill Keen Regular Crew Join Date: Jan 2004 Location: Water Valley, MS Posts: 52	<<<-- Originally posted by Anthony Marotti : <<<-- 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 :-) -->>> I'd like to know this too.... part # at B&H perhaps? Thanks.

March 8th, 2005, 01:55 AM	#17
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	If you get a filter sample pack, you might get enough blue gels to get it strong enough that it cuts out everything but blue. For example, I have a swatch booklet from Lee Filters. If you pull out all the "blue" filters and then double them over once, that's strong enough. If you have several samples then things may or may not get easier. CAVEAT1: It gets really dark. You will have to cup your hand over your eye nicely and wait for your eye to adjust for the darkness, or make some sort of screen/mask which shows relevant sections of NTSC bars or tone. I haven't CAVEAT2: I don't know if it's any better than eyeballing it, although I suspect eyeballing it is better. Just fiddle around with the hue control until you know what the wrong setting looks like, then fiddle around with it some more to remove color impurities. Then run an image with accurate flesh tones through it to make sure things look like. If you get flesh tones right you are in pretty good shape. (They might also be the hardest). A blue gel may not pass the right wavelengths of light to let you do things accurately. Plus, if flesh tones look right to your eye then you're in pretty good shape (while the gel method may not do that). Other methods: B&H lists the wratten 47B filter: http://www.bhphotovideo.com/bnh/cont...u=26457&is=REG All I can say is: Expensive!!! (probably extreme mark-ups.) The 14X18" filter is $863.95... The 3X3" is $55.95 Not worth it IMO. Some color correction books also come with a gel for you to calibrate your monitor.

March 16th, 2005, 10:44 PM	#18
Chris Byrnes Regular Crew Join Date: Apr 2004 Location: La Jolla CA Posts: 25	Consider the possibility of properly calibrating your computer monitor. DVRack from Serious Magic contains the code, switchws and instructions for doing this. This is just a minor function of the product, but very quick and useful In fact, they have a light version of the product that will do this for less money than any solution above other than gels on an already owned TV. And you can download the product from their site to try it out for 30 days. If you deice you want full function of the product on a laptop (the environment it was really designed for) then their license and activation allow you to install and run the product on two computers - so you can use full function on the laptop and just use it for calibration and monitoring on your editing system. If you are not familiar with the product it provides a full set of scopes via software emulation and captures firewire from your cam directly to disk. The sureshot function is incredible for perfecting your cam settings after the display is properly calibrated. I have no relation to SM or any of its distributors. I am just an enthusiastic user.

March 17th, 2005, 11:00 PM	#19
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	I think using a television is still a much better idea than DVRack or any other computer monitor-based solution. Why: 1- Unless you use a hardware spectrometer/calibration device along the lines of a Colorvision Spyder, a computer monitor will still experience the same amount of color shift as a television. 2- Computer monitors use different phosphors? I noticed that pure green on a computer monitor does not match the green given off by a Commodore monitor (which isn't exactly a TV), but nonetheless color reproduction is different between various monitors. 3- A computer monitor will not show interlacing, chroma crawl artifacts, underscan, or bleeding/flaring. (4- CRTs tend to be more color accurate than LCDs. Of course you can get CRT computer monitors.)