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Black Shading


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#1 Vivek Venkatraman

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Posted 06 September 2015 - 05:34 AM

Hello,

 

I am new to the red and have a query regarding Black Shading.

From what I know of it [and please correct me if I am wrong] Black Shading basically tells the camera what is Black and from that other colours are derived.

So my question is can I manipulate the camera into producing the kind of blacks that I want by holding a black card of a certain texture in front of it and reset black values ? Like can I get a milkier black or a deeper black etc etc.

Or is it better to just acheive the black you desire in post production ?

I ask because as of now I am not particularly happy with the blacks that the camera produces.

 

Just wanted to know the pros and cons of doing this.

 

Also has anyone done this ? Would love to know youre experiences .

 

 

 


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#2 Jeremy Cavanagh

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Posted 06 September 2015 - 06:57 AM

"Shading" is the traditional term used in American television for colour balancing a broadcast camera be it whites or blacks (in the UK its traditionally known as "racking" and in Australia just "CCU". This is when working in real time with a camera's output.

 

So if I have understood your question the idea with the "blacks" is to get them black or a dark shade of colour (whatever is required by the production) at a particular video level. If its a single camera you set the green channel at the level you want (using a waveform monitor and a grade 1 picture monitor) then either match the blue and red channels to the green channel or offset them slightly if you need to add a bit of colour to your blacks and this is all done initially using a standard chart. if you have multiple cameras you will then seek to match the other cameras to the intial camera both on the chart then on the set once lighting is up.

 

These days cameras, be they used for film or video, have automated this process while giving the DOP more control to take or in put an intial setting and carry it across different scenes as sensor based cameras are used in much different ways than they were when colour balancing proceedures were used for multiple camera set ups.


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#3 Brian Drysdale

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Posted 06 September 2015 - 07:45 AM

You can dig into the camera menus to make manual adjustments, but it's more usual these days to use one set up and keep the grading until post. Studio broadcast cameras still have CCUs for matching the cameras, but that's a different type of operation.


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#4 Kyryll Sobolev

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Posted 06 September 2015 - 11:44 AM

black shading with red camera is a bit of a misnomer

 

in a nutshell, specifically as it relates to red cameras, black shading is this:

- every digital chip has natural noise

- this natural noise will be different for various temperatures

- black shading looks at the noise pattern of the chip (basically the noise on black background) and stores it

- then the camera takes out the noise from the picture

 

for example, a show i just worked on - we would have a black shading map for -35º celsius shooting outdoors in february, and +35º celsius in the summer

 

in depth explanation from red

http://www.red.com/l...ing-calibration

 

excellent overview on reduser

http://www.reduser.n...ies-amp-Experts


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#5 Jeremy Cavanagh

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Posted 06 September 2015 - 02:38 PM

Good point Kyryll! I completely forgot the other use for the term 'shading' that had a different meaning for tube cameras (video) on dealing with irregularities as the tube face was scanned and now used with CCDs etc as you described the noise level from the chip that affects blacks.


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#6 Satsuki Murashige

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Posted 07 September 2015 - 02:36 AM

Kyryll is correct.

Vivek, if you just want to adjust the appearance of overall black levels or black color balance of the image, you would go to:

Settings > Look > FLUT > Shadow, or
Settings > Look > Curves,

...and adjust to taste. These settings are not baked into the raw files, they are just stored as metadata and can be changed later in Redcine X, Davinci Resolve, or whatever program you use to transcode the .r3d files. Improper Black Shading (which should be done with the lens mount port cap attached) will just result in noisy blacks with an uneven color and pattern across the frame. Unlike the 'Look' settings, this noise pattern will be baked into the raw files, you cannot remove it later.
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