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Author Topic: Gretag Colour Checker  (Read 3577 times)

Morgan_Moore

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Gretag Colour Checker
« on: October 08, 2012, 04:17:18 AM »

In the past using my Sinar54LV I could shoot a colour checker card and the raw software would lock on to the colours creating a 'perfect' profile for the shoot.

This seems most handy shooting motion for continuity and consistency between multiple cameras

It also seems a strong reason to use a camera like the BMC

Is this possible in a motion post workflow and if so how?

S
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mmurph

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Re: Gretag Colour Checker
« Reply #1 on: November 07, 2012, 09:38:42 PM »

I'll have to think through this. 

Like you , I used to create a custom profile for each still camera, starting with my 1DsII in 2004 I think. It really saved my butt on a fashion shoot, with orange/red/black checked slacks for a catalog. Hard to nail that orange! (red/yellow.)

OK. You can use a Color Checker with Color Passport or similar to create a DNG profile. You can also use something like i1 Pro to create an ICC profile, both basically via the same process - photograph some version of a Color Checker, etc.

The only software that I am really familiar with right now is CS6.  I don't think it is possible to directly apply a profile in CS6 Production Premium.  I am tired right now, up late with the election., but I can't think of a way in PP.

But you can open a video clip in Photoshop CS6.  And any edits that you make there will be added as a "layer."

When you import that clip into CS6 Production Premium, you have the option of importing everything, or importing only the "Layers."

So if you go into Photoshop and apply or do a "convert to" a profile, you should be able to import just the Layer into Production Premium.

Then if you save that Layer as a standard tool, you could just open the file and drag that layer onto a "Sequence" in CS6, and you should have your custom calibration applied.

I have 2 of my cameras profiles in Lightroom 4.0 with DNG profiles. I think I also have an ICC profile for one of the cameras that I can try to apply in Photoshop.

I'll try to do that tomorrow and report back. I'll also take a look at other color tools in Production Premium, After Effects, and Speed Grade to see if there is a way to directly apply the profiles there.

I haven't been here for a while, so I don't recall what software you are using?

Cheers!
Michael
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RFPhotography

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Re: Gretag Colour Checker
« Reply #2 on: November 08, 2012, 08:22:51 AM »

I'm not sure how that would work.  The way a DNG profile gets applied to a raw still image is at the raw conversion process.  There is no raw conversion process with (most) video.  You start working in the NLE with the video file out of the camera or out of the external recorder.  How would you go about applying the DNG or ICC profile?

If you open a video file in Photoshop you have the option to Apply, or Convert to, a different ICC profile but I don't know that this has any effect on a video file.  Apply would be the one to use.  I just tried it and there was zero visible change to the look of the image on screen.  I also have Sony Vegas Pro and as far as I know there's no way to do anything with colour profiles in that software.
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Morgan_Moore

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Re: Gretag Colour Checker
« Reply #3 on: November 08, 2012, 09:09:20 AM »

It should work for raw or not - of course a non raw image could 'break'

Touched on here ..

http://notesonvideo.blogspot.co.uk/2012/05/adobe-speedgrade-webinar-notes.html
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Sam Morgan Moore Cornwall
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RFPhotography

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Re: Gretag Colour Checker
« Reply #4 on: November 08, 2012, 10:47:28 AM »

They don't actually say how the colour chart is used for colour correction.  In that case, my expectation is that they're not using a profile of any kind to do the correction, but rather taking a few frames of the chart at the start of the clip then 'eyeballing' the colour in post.  If you're working with two cameras you can do the first, figure out what the colour numbers are then manually adjust the footage from the second camera till the numbers match (or come very close) but you're still doing it by vision rather than applying an 'accurate' profile.

The point I was trying to make, Morgan, about non-raw is that video files are baked in.  The colour is essentially set.  As is white balance.  Editing video is almost like editing a JPEG still file.  You don't have all the flexibility you have with a raw image.  So while you can make corrections, the effectiveness isn't going to be the same and the end result isn't going to be as good. 
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Morgan_Moore

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Re: Gretag Colour Checker
« Reply #5 on: November 08, 2012, 03:25:15 PM »

The camera i initially mentioned was raw.

In general I guess the software makes a correction to put the colours in the right places

indeed with a thin camera shot off balance that could 'break' the footage

S
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Sam Morgan Moore Cornwall
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RFPhotography

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Re: Gretag Colour Checker
« Reply #6 on: November 08, 2012, 04:51:10 PM »

You're talking about the Black Magic?  Again, very different from working with most video files.  Not a lot of people have Reds or Black Magics or Arris (do some/all Arris shoot raw?), though right?

You should have more flexibility working with raw video than with video that's already baked in.  But then we come back to the question of 'how' the colour checker card is used.  Is there a way, as with raw still images, to apply a custom profile to correct colours?  Or is it a visual exercise, fiddling curves and filters till it 'looks' good?
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Morgan_Moore

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Re: Gretag Colour Checker
« Reply #7 on: November 08, 2012, 05:27:05 PM »

My original post refered to the BMC - the black magic :)

and the question was indeed how!

no not by eye

S
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Sam Morgan Moore Cornwall
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Michael Schoenfeld

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Re: Gretag Colour Checker
« Reply #8 on: November 10, 2012, 11:03:00 PM »

Morgan,

Love what you contribute here.

Rookie poster - long time lurker.........

I've met Mr. Reichmann/Mr. Schewe at Photo+Expo - such wonderful people.

I shoot all Canon (raw) for stills, but purchased an FS700  in August - love it, as long as I can control DR however possible.

"Baked jpegs" - on this camera, post not withstanding, not too bad.

It's amazing camera (the "raw" dust hasn't settled yet IMO - 1-2 more years). I'll wait for the war to even out a little more.

Thought this might be of interest concerning this issue - not all "raw" is created equal:

http://nofilmschool.com/2012/11/canon-c500-shipping-raw-4k/

Schoenfeld
www.michaelschoenfeld.com

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Michael Schoenfeld

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Re: Gretag Colour Checker
« Reply #9 on: November 10, 2012, 11:21:48 PM »

FYI, I remember reading a few years back, that "getting the WB dialed in" (whatever that means to a person) at the time of shooting, can improve the raw file's ability to be accurate in post. Not sure if I buy that...... I've played both ways.

Sometimes I do....... sometimes I don't.

Schoenfeld
www.michaelschoenfeld.com
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Sareesh Sudhakaran

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Re: Gretag Colour Checker
« Reply #10 on: November 11, 2012, 06:55:42 AM »

There's no reason why it shouldn't with firmware.

The key issue is that the color (even on a chart) will change from shot to shot, depending on lighting. What's the point of locking on different versions of the same color? In post you'll just make it tougher on yourself. Or am I missing something?
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RFPhotography

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Re: Gretag Colour Checker
« Reply #11 on: November 12, 2012, 07:20:04 AM »

That's the point of 'how' the chart is used.  If it's just adjusting by eye then it seems pretty pointless, yes.  But if, as with still photography, there's a way to automate the correction so that everything comes back to the same starting point then it may make some sense and speed up the editing workflow.
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