From: "Bob Currier" <rcurrier@synthetic-ap.com>
To: "After Effects Mail List" <AE-List@media-motion.tv>
Subject: Re: [AE] ASC_SOP & ASC_SAT values
Date: Wed, 31 Jul 2013 19:44:18 -0700
Message-Id: <20130801024418.389588797@smtp.synthetic-ap.com>
In-Reply-To: <list-5161535@media-motion.tv>
References: <list-5161535@media-motion.tv>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable

"SOP" is "Slope, Offset, Power" in ASC CDL speak. We chose different names =
because many people calculate lift/gamma/gain in different ways.

Slope is gain (multiplication). Offset is lift (addition). Power is gamma =
(y^(1/x)). Saturation is saturation.

To reverse it, enter the reciprocal of slope as your "gain." Enter the =
reciprocal of power as "gamma." And enter the negative of offset as "lift." =
Enter saturation as the reciprocal of the CDL value.

The gain setting should work regardless of the color correction app. The =
gamma value, however, may need to be entered as a reciprocal. The lift value =
is the hardest to deal with. Many apps adjust gain along with the lift =
setting, while the ASC CDL is a pure offset.

Or use Color Finesse within AE which can read ASC CDLs directly, so you'd =
just need to invert the values in the .cdl file, then load it in.

With all that said, is the CDL really your "viewing LUT" or is it =
representation of the color correction that's been done, which is the normal use for =
a CDL=3F

----- 
Bob Currier                                  rcurrier@synthetic-ap.com
Synthetic Aperture                           www.synthetic-ap.com
Helping Make Your Work Look Its Best

On Thu, Aug 1, 2013 6:41 PM, David Torno <torno@sydefxink.com> wrote:

>Curious question to anyone who has done a lot of CDL (Color Descision
>List) work. I'm use to using a generic Cineon Log to Lin for viewing and
>then doing a reverse process with Cineon Lin to Log for final output.
>Not once have I ever gotten a proper LUT on a project in the 13+ years
>I've been doing this work. Sad, very sad. Anyways, someone finally has
>some CDL values (not an actual LUT file mind you) and I can easily,
>manually, input the values into Colorista - Free, but how would I do a
>reverse of this properly=3F I'm assuming this CDL is essentially my
>"viewing" LUT and I would need it's opposite to reverse it all back with
>VFX applied. Did that make sense=3F Thanks for any insight.
>
>What the editor exported for me, is an EDL that contained these lines as
>well as other clip data.
>
>*ASC=5FSOP (1.0000 1.0000 1.0000)(0.0000 0.0000 0.0000)(1.0000 1.0000 =
1.0000) 
>*ASC=5FSAT 1 
>                                    
>                                          
>The ASC=5FSOP and ASC=5FSAT data exists, even though they are default
>neutral values. I'm hopeful that he will be able to get the actual CDL
>values that he is seeing in AVID.
>
>
>--
>David Torno
>Visual Effects Artist and Supervisor
>http://www.ghosttownmedia.com
>david@ghosttownmedia.com
>O: 213.739.2290
>C: 818.391.6060
>------------------------------------------------
>http://www.sydefxink.com  (main portfolio)
>http://aeioweyou.blogspot.com (vfx tutorials and AE scripts blog)
>http://mactex.blogspot.com  (free textures blog)
>
>
>
>+---End of message---+
>To unsubscribe send any message to <ae-list-off@media-motion.tv>
>