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Film Scientist ACES Workflow Revisited

Below is a detailed methodology for my 12bit F35 ACES workflow using an AJA LUT box.

F35 to AJA LUT box to Gemini

Begin with the F35 Camera set to a base ISO of 450 (0db). Frame rate should be set to _24 fps 12 bit (not 23.98) with S-Log Gamma and S-Gamut. Connect the dual link IF 4:4:4 outputs to 3G inputs of the AJA LUT box, the output on the LUT box should be taken from 3G single link output which converts the F35’s 12bit PsF signal to a true progressive signal the Gemini Recorder can accept. A 512 GB memory card will yield roughly 37 minutes @12bits/24 fps. Use Convergent Design’s transfer tool to unpack 12bit files to 16bit, otherwise Davinci will not be able to decipher the 12bit DPX files.)

ACES setup in Davinci

Import media to Davinci (I’m using v10.2, because of node issues on v11 due to an old video card). In master project settings, set project to Davinci ACES color space. Since there isn’t a native IDT readily available for the F35 camera within Davinci, leave IDT alone. We’ll use a 3D Transform LUT to replicate the IDT. Set ODT as SRGB (if your grading on a computer) or Rec 709 (if you’re going out to Broadcast/Bluray)

davinci aces colorsrgb

Transform LUT

Apply the attached transform LUT on the timeline to all your clips; it will serve as a replacement for the IDT. This 3D LUT transforms S-Gamut to ACES and S-log to linear, without affecting color in a negative way so you can apply it to all your F35 footage as a neutral base. It places the footage in an optimal area for ACES so you can begin grading and make a minimum of adjustments.

Film Scientist ACES LUT

Color correct your whites, blacks and grays on the waveform.
Tweak color using the vectorscope as guide. Throw in an overall curve to taste.
Or if you are on Davinci 11, and have a One Shot Card you can use the automatic color match based to skip the manual color correction. While the color match within Davinci is technically accurate I still prefer to adjust the sliders myself (in a minimalist fashion) to get to a similar slightly cleaner result, then I proceed to grade it.

one shot

one shot click

one shot grid

Apply Neat Video to denoise
Because the uncompressed 12 bit files provide such a huge amount of real data, Neat video can do a pretty amazing job of recovering all the detail and while clearly identifying all the color information that was captured. If you get a good shot of the gray card, you can get a 90% quality level when creating a camera profile which does wonders for differentiating noise from detail. The ability to generate a picture with no compression artifacts is pretty amazing.


The reason to use ACES instead of yRGB.
ACES takes the output medium into consideration so corrections stay within intended gamut and no information is lost. In the future, when rec2020 monitors become available you will simply need to switch an ODT rather than re-color-correcting for a new medium. Think of ACES as a huge coloring box with unlimited crayons. By transforming all the data into an even larger ACES color bucket, and shifting the log curve back into linear space all the data original is retained, you get crisp and clean data while manipulating your F35 footage. When you grade in it, you don’t lose any information because ACES space contains every color your monitor could possibly produce. Working in linear gamma also allows you to easily intercut footage to other cameras or cg elements without pesky color science getting in the way.


Sony F35 ACES workflow

I always wanted to utilize an ACES workflow with the F35 Camera, but attempting to re-create a workflow for a camera that was popular 5 years ago with economical off-the-shelf software was like a needle in a haystack… Existing grading software that utilized proper F35 IDTs cost many thousands of dollars, and newer software skipped this particular camera, only including IDTs for the F65, and F55.

Why bother with ACES?

Because it maps the color of each camera to achieve consistency amongst various brands and allows for closer seamless integration of CG elements. By utilizing an image device transform (IDT), ACES removes the secret sauce/color science of each camera manufacturer (meant to hide the deficiencies of each), and transforms and linearizes the data/light captured from the imaging device without losing any information.

In the purest sense, an IDT maps what the sensor data captured into a distinct, discreet numbers that correlate to the predefined ACES color workspace (which encompasses more than our eyes can see). In order to utilize ACES correctly, it requires the use of an IDT (image device transform) to properly map the camera’s luminance values, a reference rendering transform (RRT), and output device transfrom (ODT), eg. our monitor or projector. Without them, we’re just doing random transformations without a common baseline.

My search for a usable implementation of the F35 IDT led me through a deep rabbit hole where I downloaded random Japanese software from Sony & played with outdated rudimentary cineon and rec709 luts. 1D LUTs are a great intermediary step, and I still wanted to use them in the offline stage, but I felt they were ultimately destructive to the data in the grading stage. My search ultimately led me to a simple solution that uses After Effects, OCIO, and LUT Buddy.  Hopefully this blog saves you the headache I went through to find a low cost/workable ACES solution for this amazing camera…

The Goal

My original goal was to create a render-less editing workflow that allowed me to apply a proper 3D LUT /log dailies transform to uncompressed log DPX files in Premiere (Sort of a one-box solution with final output through After Effects.) Using an SSD/Thunderbolt setup, I wanted to edit with the original files and eliminate the need to create dailies or have the option of changing them at any given time. I also wanted workflow that took me straight to finishing without excessive roundtripping. This process still requires rendering in the timeline, but allows us to utilize the same original log files throughout the entire process (and avoids those strange gamma shifts when using formats like ProRes.) I am able to output in 10bit from Premiere using 3D LUTS if I’m in a rush or I can proceed to finish in After Effects in full 32bit floating point.

The Method

It starts with After Effects, and you will need to download the free plug-ins listed at the bottom of this page.
Option 1: apply IDT transform using OCIO, create dailies LUT that removes the log and maps all the S-Log values accordingly.
Option 2: apply IDT transform, grade using Colorista plug-in, output a graded LUT that we can use for offline editing.

The process is pretty basic,
apply LUT Buddy effect to desired clip,
select a ‘Draw Pattern’
pattern: (3D 32)
(This will read the original RGB data that is baked into the file, before transformations)
add OCIO effect to same clip, click on ‘convert’ button, change settings to:
(configuration: aces)
(input: slogF35)
(output: aces)
add second OCIO effect to clip, this time click on ‘display’ button, change settings to:
(input: aces)
(transform: RRT)
(device: sRGB)
(OPTION2: add Colorista effect or perform additional grading if needed
apply additional LUT Buddy effect to clip, select ‘Read Pattern’
pattern: (3D 32)
click ‘Options…’ menu s
select ‘Export LUT’, for file format select Apple Color (.mga)

Apply the mga. LUT to clips in Premiere for an offline LUT.

OCIO becomes our ACES foundation for any grading in After Effects.

Overall Finishing Pipeline

DPX > load single clip to AE > create dailies LUT

Apply dailies LUT to DPX footage  in Premiere > Dynamic Link > AE

Finish in AE (ACES), track, composite, etc…

General notes:

Make sure to set up working space in After Effects to 32bits per channel.
In order to playback uncompressed DPX files you need a disk subsystem capable of +350MB/s (at 24fps the computer is moving 200MB/s, not including audio)

Why go to the trouble of doing this?  What are the Benefits?

1. The proper gamma transform for F35 footage gives us solid a neutral reference to begin the grading process . White point, black point and gamma RGB, are properly mapped according to the camera’s S-Log spec.
2. Once the proper F35 IDT is applied, the footage needs fewer adjustments and color transformations to make it look good. If you’re capturing the footage as intended by the S-Log spec the footage should look pretty good, requiring minimal grading to get the image looking good/right.
3. It’s a simple, free solution that runs on slightly older mac computers if you have fast drives.
4. To my eye, the ACES mapping in After Effects gives the skin tones a more natural look than starting from scratch or using a basic LUT, and also allows us to use the full power of After Effects 32bit floating point pipeline.
5. No longer have to commit to baking in a LUT onto dailies footage or have multiple sets of original files. I love the latitude of working with uncompressed 2K files which allows me to do more things in one box without excessive round-tripping.
6. Allows ability to test different LUTs or grades while editing in Premiere.
7. LUTs created easily translate to other finishing programs allowing us to work with elements from different apps and be assured that color/gamma is consistent across them all.

Software you will need to download:

OpenColor IO for After Effects
This plug-in is the missing link for obtaining a working F35 IDT! That you Brendan! OpenColorIO is Sony’s solution for color management. It’s a very smart way in dealing with color in scene linear. OCIO is how the big boys like Sony Imageworks deal with color. It removes all our problems associated with the different gammas of quicktime and ProRes… Color matches from app to app.

DPX Plus
Free plug-in that allows us to read all flavors of DPX in Premiere and After Effects…
(Brendan also makes other awesome plug-ins that are really valuable for VFX pipelines. Check out his EXR plug-in. EXR is a great file format created by the godfather of visual effects ILM.  EXR is the go-to file format for most finishing pipelines because of its openness and expandability.

LUT Buddy for Premiere, LUT Buddy for AE
This plug-in reads and creates look up tables. It’s free and allows us import 3D LUTs into Premiere, apply to clips in one fell swoop. It gives us the option to output 10bit color quickly from Premiere, or move back to a 32bit floating point color pipeline for finishing in AE. The demo of the software suite should include a copy of LUT Buddy.

Sony F35 Camera Mojo
With the early R&D help of Panavision, Sony used its sizable resources to develop an amazing CCD chip that captured a color gamut wider than film. It’s basically one of the first and last ccd’s made in the S35mm size before the CMOS fabrication process became mainstream. The red, green and blue dyes on the F35 CCD were some of the most accurate of their day, but it made the chip very expensive to produce. Color science is a big thing on this camera, and short of the F65 or maybe the latest Alexa,  I feel few cameras capture better color. The F35 CCD is natively balanced to a color temperature of 3200K so the sweet spot for the sensor is based on standard tungsten lighting, skin tones and warm sources look great. Most CMOS silicon chips today have a native color temperature of 5000K. So while many CMOS chips are great at capturing the blue sky and daylight, they tend to be a little more deficient or clinical when it comes to skin tones. While we can pump up the deficiencies with grading, it’s one of the few cameras that capture full resolution RGB color data per its output resolution.  I hope this blog entry can help shift back our conversation to capturing and translating color tonality & dynamic range, the true hallmarks of S35mm film. While newer camera have great resolution, and bring out every wrinkle, crease, or imperfection, I would like to say that the motion pictures we saw in the past 50 years never resolved much beyond 2K by the time they were projected in theaters (IMAX notwithstanding).  So even after five years this camera still captures great tonality, and offers a similar creamy, luscious look that we loved with film.