[Tig] Apple Color strange behavior

Nagy Eszter nagy.eszter at gmail.com
Sat Sep 11 07:46:31 BST 2010


Hey Guys,

Im not sure if my problem is anywhere related to this topic, but Im hoping
someone else has experienced it too.

Im grading RED footage for DI in Apple Color with a film print viewing lut
loaded. The RED settings are all set to RED Log, the output format is dpx.
 I tried all 3 different render settings on the preferences page, which
relate to black and white point mapping, but I never get the same density as
on the output monitor (projector).
The best looking render is with the linear setting but its still
significantly darker. (Cineon type is even worse).
The strange thing is, if I enable the option to burn the viewing lut into
the render, than I get the exact same result as on my screen.

Anyone has seen this before?

thanks,


Eszter Nagy

Freelance Colourist
+36 3050 85599



On Thu, Aug 12, 2010 at 11:37 PM, Jean-Francois Panisset <panisset at gmail.com
> wrote:

> Sohonet http://www.sohonet.co.uk sponsors the TIG.
> Digital Vision supports the TIG.
> ====
>
> There has been a long-standing assumption on the Mac that all
> RGB-encoded media has a native gamma of 1.8, whereas YUV/YCbCr media
> has a native gamma of 2.2. This means that Mac libraries and apps (and
> QuickTIme in particular) are forever applying "helpful" 1.8 -> 2.2 ->
> 1.8 gamma conversions, which works out to a gamma lift or drop of
> around 1.222.
>
> An example of this: take a QuickTIme created on a non-Mac platform
> using an RGB-based codec, bring that into QuickTime Pro or Compressor
> to transcode to a YCbCr-based codec (MPEG2 for instance), and you will
> find a gamma lift of 1.222 has been applied.
>
> The only Mac-based application that I know of that doesn't mess with
> gamma at all is Shake (Nuke may also be in the clear, but I haven't
> tested it yet). There's a helpful article in the Apple KDB that
> explains the differences between the ways Shake and FCP deal with
> gamma, I'm guessing that Color behaves more like FCP than Shake:
>
> http://support.apple.com/kb/HT2912
>
> There were rumors that under OS X 10.6, the default gamma for RGB
> media would be changed from 1.8 to 2.2, but I have not been able to
> verify if this is indeed the case.
>
> JF Panisset
> MPC
> Santa Monica, CA
>
> On Thu, Aug 12, 2010 at 9:51 AM, Rob Lingelbach <rob at colorist.org> wrote:
>
> > Instead, I see a curve that appears to have a gamma of 1.22.  I have
> attached a figure of the RGB scopes below.  If I intercept the signal Apple
> is outputting to the grading monitor, it confirms this gamma 1.22 curve is
> indeed being transmitted to my grading monitor.
> >
>
> _______________________________________________
> http://reels.colorist.org
> http://tig.colorist.org/wiki3
>


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