Colour correcting through a graphic card.

Amadou

Amadou

Carbonite Member
It seems to me that colour correcting a clip while monitoring it on a computer screen connected to a graphic card isn't the way t go. Am I wrong? Does one not need to monitor through a TV monitor and blackmagic type card? Is there anything other or better than Blackmagic cards for monitoring colour correction?
 
You are correct that looking at your footage on a broadcast monitor fed by something like a blackmagic card is better than looking at it in the GUI displayed on a computer monitor fed by a computer GFX card. There are different levels of BM cards so there may or may not be something better depending on what you currently have.
 
Amadou said:
It seems to me that colour correcting a clip while monitoring it on a computer screen connected to a graphic card isn't the way t go. Am I wrong?
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For Premiere Pro, CS5 and later, you don't actually need a converter box. Your graphic card is just fine. Other NLEs probably require a converter box.

As to the use of a computer monitor... depends on what you are trying to accomplish. If you are delivering to be seen on a computer monitor (YouTube, etc.) then color correct on a computer monitor. If you are delivering to be seen on a HDTV (DVD, Blu-ray, broadcast, etc.) then you need a monitor that can show you the correct color space (REC.709 in this case). Very few computer monitors can do this, so you need either an HDTV or a production monitor.
 
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Interesting article, Bruce. It left me a little confused, however. It suggests, without explicitly stating, that with my CS6 I don't need to send a 10-bit SDI signal to a proper production monitor, but can instead view it right on my apple cinema display. This seems a little too good to be true.
 
Bruce Watson said:
If you are delivering to be seen on a computer monitor (YouTube, etc.) then color correct on a computer monitor.
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That's not the best advice. Where the final product ends up will not change the primary requirement of color correction, which is acurate display of the signal. And that can rarely be achieved with a computer monitor or hookup via graphics card, even with CS5 and later. The issue isn't necessarilly with Premiere Pro, it's with the potential for the OS and the graphics driver to alter the signal, which I don't believe you can avoid when hooking up a second monitor to the GPU. Dedicated I/O devices are designed to pass the signal accurately, without alteration.

You don't want to be compensating for too much red which is caused by the display, and not an excess of red in the video itself.
 
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Ideal is a Broadcast Monitor and hardware interface.

Next a decent Computer Monitor well calibrated and set up. Is more than adequate for broadcast and "other" computer display.

I will point out by way of examples... the best print work you might ever see in a high end magazine..is all done on computer monitors.

Much of the work you see in TVCs and feature films is done on computer monitors at various stages of the pipeline. CC/grade , FX and comping.

Broadcast QC is done on monitors that may or may not be BC standard. This reflects standard viewer experience but QC is all about the scopes.
 
Amadou said:
What specific monitor models and/or criteria would you recommend?
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As always, you need to set a budget to work with, as it doesn't make sense for someone to suggest a $12K monitor if your budget is $1200.

And secondly, you need to learn to use a waveform monitor and vector scope, as they will likely be more accurate than an uncalibrated monitor.
 
Jim Simon said:
That's not the best advice.
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It's not advice; it's fact. That Pro Video Coalition article gives the details. I've proven it myself, using my dumb ol' laptop with a GTX 285m card and PPro CS6. Color corrected by running an HDMI cable from laptop to HDTV, did my work, burned a DVD, played the DVD back to the same HDTV using a Panasonic DMP-BD60 Bl-ray player. Found a frame at the beginning of a chapter and paused the DVD. Found the same frame in PPro. Switched back and forth on the HDTV between the two different HDMI inputs. Frames nearly identical. The video looks nearly identical. I then ran the DVD around the neighborhood and looked at it on a number of different disc players and TVs. It looked fine everywhere.

IOW, Pro Video Coalition is correct, Adobe is sending the correct signals out of the video card without any need of any additional hardware. AFAIK, Adobe is the only NLE doing this.

As to monitors, my point is to use a monitor that shows you the same color space of the intended target. Correcting on a production monitor (or an HDTV, hopefully calibrated) which shows you REC.709 will give you somewhat different results when viewed on a computer monitor in SRGB or AdobeRGB. The two color space's colors are close, maybe "close enough", but the two color spaces use different gammas, and different black and white points (0-255 vs. 16-235). Try it. You'll see the difference.
 
Shooter said:
... the best print work you might ever see in a high end magazine..is all done on computer monitors.
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Apples and oranges. You can get a computer monitor into a fully color corrected workflow for stills. You can get it to show you the CMYK color space used in printing. You can even softproof and get it to show you the same paper as the magazine stock. IOW, you can get a very close match between what you see on the computer monitor and what comes off of the offset press.

But there isn't the equivalent workflow for video. You can't get a video monitor (unless you spend quite a lot) to show you your footage in the REC.709 color space. I think there a couple of EIZO monitors that can, and the HP dreamcolor does (did? still available?).
 
Rec709 is identical to sRGB which is the standard color space of pretty much any computer display. A display which is calibrated for sRGB is in fact calibrated for Rec709, if you calibrate the grayscale to a corresponding gamma curve. There are a lot of computer displays which cover rec709.
 
Point made. There is an equivalent workflow in video. Get a decent monitor. They are available if "you spend quite a lot".

Still photographers dont buy printing machines as preview devices. :smile:

But there isn't the equivalent workflow for video. You can't get a video monitor (unless you spend quite a lot) to show you your footage in the REC.709 color space. I think there a couple of EIZO monitors that can, and the HP dreamcolor does (did? still available?).
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cpc said:
Rec709 is identical to sRGB which is the standard color space of pretty much any computer display. A display which is calibrated for sRGB is in fact calibrated for Rec709, if you calibrate the grayscale to a corresponding gamma curve. There are a lot of computer displays which cover rec709.
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Nope. See post #14 by David Jones below.
 
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The difference between sRGB and rec709 is that sRGB explicitly defines a display (output) transfer curve and rec709 does not. Rec709 only specifies an encoding scene/linear to camera transfer curve. It does not define a decoding gamma. You can only compare sRGB and rec709 encoding curves, but NOT display/output curves, because rec709 doesn't have any. This lack of display gamma standard is the reason people are coloring rec709 under gamma of 2.2, 2.4, 2.35 or whatever they figured looking up the ceiling.
So with gamma effectively decoupled from primaries and white point, you can calibrate any sRGB monitor to whatever gamma you see fit. For all practical purposes sRGB is the same as rec709 as a color space, or gamut. And it most certainly is the same when it comes to monitoring capabilities.
 
Bruce Watson said:
Apples and oranges. You can get a computer monitor into a fully color corrected workflow for stills. You can get it to show you the CMYK color space used in printing. You can even softproof and get it to show you the same paper as the magazine stock. IOW, you can get a very close match between what you see on the computer monitor and what comes off of the offset press.

But there isn't the equivalent workflow for video. You can't get a video monitor (unless you spend quite a lot) to show you your footage in the REC.709 color space. I think there a couple of EIZO monitors that can, and the HP dreamcolor does (did? still available?).
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the Eizos can do Rec 709 quite well after a proper 3D LUT calibration:

here's a very detailed Eizo calibration guide & workflow: Eizo CG275W Calibration Guide Using Lightspace And ColorNavigator

- Mike
 
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