[Tig] ProRes444 necessary when grading BW

David HJ. Lindberg david.hj.lindberg at gmail.com
Sat Mar 16 11:51:28 GMT 2013


So many good answers, thanks a lot!

In my case I'm coming from colored raw files converted to colored ProRes444
which I then will grade to black and white. But now I understand that 444
would give me more grey values per pixel than 422 would.

Joe,
"but a matrix of RGB in a roughly 70/20/10 mix."
Do you mean it's 70% of the green channel and 20, 10 of either red and
blue? If so, which is 20 and which is 10?




2013/3/15 Joe Owens <jpo at prestodigital.ca>

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> =====
>
> It really depends on what's in the container.  ProRes 4:4:4:4 can be
> either Y'CbCrA or RGBA.  If it was Y'CbCr, and transferred as
> luminance-only, you are actually grading 4:0:0:0.
>
> If the ProRes container is an RGB  color scan of something originally B&W,
> then it's likely R=G=B, which is just a waste of bandwidth; but if your
> ProRes is a color picture that you are making B&W, then a nice RGB 4:4:4
> could have some benefits.
>
> Recall, of course, that Y', the luminance component of a color signal, is
> not actually 100% Green, but a matrix of RGB in a roughly 70/20/10 mix.
>  Alexis Van Hurkman covers some approaches to black & white utilizing the
> Resolve color mixer quite nicely in a few of his tutorials.
>
> If you are grading a color scan to create the black & white, it depends on
> whether you want to redefine the Y' matrix.  There used to be a cheat on
> most telecines that copied the green channel into all three to create a
> monochrome signal, but it never looked as nice as grading for a neutral
>  and then desaturating.  Black and White stock has a different spectral
> sensitivity (and this differs between acetate and nitrate, and so on), so
> when anyone simply refers to "just black and white",  they're missing the
> nuance.
>
>
>
> On 2013-03-15, at 3:59 PM, David HJ. Lindberg wrote:
>
> > I started to wonder this week if it's necessary to use ProRes444 files
> when
> > grading something bw?
>
> Joe Owens
> Presto!Digital Colourgrade
> 302-9664 106 Avenue
> Edmonton, Alberta T5H0N4
> +1 780 421-9980
> jpo at prestodigital.ca
>
>
>
> _______________________________________________
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> http://tig.colorist.org/wiki3
>



-- 
David HJ. Lindberg
My films: http://vimeo.com/davidhjlindberg
My blog: http://davidhjlindberg.blogspot.com/


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