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External Monitor Calibration - Best workflow

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Neill Jones
External Monitor Calibration - Best workflow
on Sep 4, 2012 at 11:48:21 am

Hello,

I currently work in a post house that has had Da Vinci resolve installed. It's Run via a Decklink Extreme card and monitors on a Cine-tal Cinemage 2000 or 4000. I'm not entirely sure which. The problem that i'm having is that I don't feel that the monitor has ever been properly calibrated and looking at footage output to other monitors in the building the pictures do not match.

There is an i1 display pro that is attached to it but when it has finished it's cycle it sets the monitor to Single link 4:2:2 when our card is set to output Dual link 4:4:4 and when you set it back to Dual Link 4:4:4 it loses all the calibration information. I've also read on other forums that the i1 is more for print than video.

So this leaves me with a number of problems. I can try and calibrate the old fashioned way using SMPTE bars but I'm unsure as to whether I can trust the source. I've imported SMPTE bars into AVID using the hard import option and AMA and they both yield different results. (The format of the test patterns that come with AVID will not import directly into Da Vinci) Logic dictates that the AMA option is more trustworthy than the imported version as it is referencing the original media but even then can I guarantee that AVID what AVID is displaying is a true colour representation that I can calibrate against. I would have thought that previewing the bars out of Da Vinci would be more accurate to calibrate against than AVID in which case if I export the AMA linked file out of AVID to Da Vinci how can I guarantee the preservation of colour information? I don't trust .movs at all but out of the codecs, again as it's related to the Blackmagic software I would have have thought that it's own 10 bit codec would be best.

Can anyone give me any advice on this or recommend a best work flow to ensure that my monitor is correctly calibrated.

Kind regards

Neill Jones


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Dmitry Kitsov
Re: External Monitor Calibration - Best workflow
on Sep 4, 2012 at 4:34:28 pm

Make your own HD bar chart in resolve with power windows and using waveform and vectoroscope as a guide. This way you will be sure what color values are generated.


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Joseph Owens
Re: External Monitor Calibration - Best workflow
on Sep 5, 2012 at 3:16:20 pm

[Dmitry Kitsov] "Make your own HD bar chart in resolve with power windows"

You can't be serious.

I know people try to make their own charts with Photoshop and various other graphic programs, but let's just say that conflicting color profiles and a general unawareness of what goes into making a bona fide reference test signal generator goes beyond what a lay person, or a general operations technician can achieve. Color bars, for example, as simple as they may appear, are the result of a matrixed luminance/chrominance data field, and if you wish to create something similar to an EIA/SMPTE color bar standard (and this whole argument is about creating a universal reference) you will have to re-create the work that was done by a team of engineers in the '50s, who actually understood all the ramifications of what they were doing... in terms of gamma, black point, white point (peak and APL), luminance/chrominance matrix (not just adding R+G=Yellow, for example -- you get the wrong Y' result), and added to that the fact that RGB/Cy,Y,Mag are not equidistant in relative phase.

Underscoring this exercise in futility is the reality that even if you were to somehow fluke a perfect SMPTE color bar reference, it is only valid for composite (baseband NTSC/PAL) transmission, which we don't do anymore. There is no way to use SMPTE color bars to set up the overall emissivity of the display (which affects everything else), so roughing in the hue, black point, and saturation using blue-only (especially with a do-it-yourself image) is like lobbing a baseball back over the stadium wall and hoping it will land exactly in the middle of home plate. The national lottery is a better bet.

I absolutely understand the desire to "do things right". But in order to do things right, you actually have to "do things right".

But this is not much worse than camera assistants photocopying framing charts to shoot lens tests.
"But what would be wrong with that?"

jPo

"I always pass on free advice -- its never of any use to me" Oscar Wilde.


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Robert Houllahan
Re: External Monitor Calibration - Best workflow
on Sep 6, 2012 at 12:53:23 am

Yeah what JPO said.

I would recommend at least a X-Rite Hubble with Light-Space, Cine-Space or the new Cal-Man studio for a proper calibration and LUT creation. Especially if you are thinking about wider gamut color spaces than REC709.

-Rob-

Robert Houllahan
Director / Colorist
Cinelab Inc.
http://www.cinelab.com

MAHC-PRO 6-Core 3X GTX285 20Tb SAS Wave Panel Panny 11UK SDI Plasma. Light-Space CMS + Hubble


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Dmitry Kitsov
Re: External Monitor Calibration - Best workflow
on Sep 6, 2012 at 5:17:50 am

Hmmhmm, I guess we do need a punctuation mark for sarcasm...


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Yoram Tal
Re: External Monitor Calibration - Best workflow
on Sep 6, 2012 at 3:45:58 pm

To Start I Would Google Smpte Bars and download a few files they are all over the internet.

I would love to know from more people how they calibrate their monitors...

I do use the i1 but I line things to match the resolution I work with every time (GIANT pain.)

I hope this helps.
Tal


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