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LOG profiles, color science, gamma curves, RAW, transforms… Gosh, I hear ya. It’s really tempting to skip the headache of color spaces when working on VFX productions with professional video production houses.

We just want to say that from our experience on VFX projects, it’s always worth working on the RAW LOG files instead of the graded footage for a few important reasons.

  1. Maintaining Dynamic Range
  2. Pixel Integrity and information
  3. CG production consistency

1. Maintaining Dynamic Range

High-end productions shoot on quality cameras for many reasons, and one of them is for capturing a high dynamic range; Details and information in the highlights, and shadows. All this extra information in the image provides creative flexibility in post-production.

Handing over color graded images to the VFX house usually means a premature creative destruction of information. Limiting the creative control very early on in the pipeline.

Example of RAW vs ‘Graded’

Left: RAW footage in LOG, color transformed in NUKE
Right: Same footage, but with the transformations baked into the image

You can see how much information would be lost in image on the right. Pay attention to the highlights in the sky and on the wooden table. When we dim the image, you can see that there is much more detail and color in the LOG file.

Now for example, say we rendered a CG metal item and placed it on the table, the reflections on this metal item would be severely compromised if it were to be reflecting the sky from the image on the right.

2. Pixel Integrity and Information

During the grading process and export, pixel values and data integrity may be crushed or stretched to their limits. So whilst the export as a whole may look perfect, these pixels might be prone to artefacts later on.

Final image compression should take place at the end when the video is delivered to the client. Crushing pixel data before handing it over the VFX house is premature and limits the flexibility and overall output quality throughout the pipeline.

Example of RAW vs ‘Graded’

Left: RAW footage in LOG, color transformed in NUKE
Right: Same footage, but with the transformations baked into the image

Let’s call this the ‘resting’ form. Where both images essentially look identical.

Here we have applied a heavy saturation boost to both images to illustrate the effects of poor pixel integrity artefacting. You can see that although in the ‘resting form’, both images look identical. But if we start pushing them, the image on the right starts to break into blocks.

Zooming in to a more detailed comparison, we can see the the image on the right really breaking into blocks of color artefacts. The value of maintaining pixel data integrity from the RAW LOG file vs a compressed ‘graded’ file allows the colorist to push the image to this crazy saturation without it ‘breaking’ even after CG and VFX elements are composited on to the image.

Image compression is for the end, not the start of the production
Unfortunately, if we work on an already compressed graded file, and deliver it back, and should the project require tweaks to this shot, the flexibility to push or pull this image is severely handicapped.

3. CG production consistency

Working in CG for a VFX production relies on a lot of real-world understanding of color and values. Baking in color-transforms and grades before using these footages in the CG pipeline muddles up these values and forces the artist/software to compensate for the color grade/transform.

Example of RAW vs ‘Graded’

Left: RAW footage in LOG, color transformed in NUKE
Right: Same footage, but with the color grade baked into the image

Even in the very unlikely scenario where the client and production house have ‘locked’ in the color grade (meaning no more changes), it’s extremely difficult to work on the graded footage due to the variety of color variations a particular object can have after a color grade. — Blue shadows, purple shadows, orange shadows. Lot’s of things that would require lots of magic to physically reproduce faithfully.

A lot of the work done within the VFX pipeline is re-creating the real world—in CG. So in the same way a video production house doesn’t physically paint the objects on set to match a color-grade, the CG scene should not be ‘physically’ altered to match a color grade.

Looking at the image on the right, you can imagine how challenging and inaccurate it would be to work off the color graded image, versus the RAW image on the left.

Project example: Jasmine Sokko — Tired

Here’s an example of a project where we worked from the RAW footage, and delivered back the footage in the same colorspace so the colorist can continue to work on the footage as before, but now with a giant CG hologram cat. :3 — See project here

RAW anamorphic footage in ARRI v3 Log C Color transformed in Nuke
(ARRI v3 Log C >> Linear sRGB)

Composite of 3D renders

Color transformed in Nuke, back to ARRI Log C.

You can see that through this workflow, the delivery from VFX house (us) to production house is essentially the same footage, in the same colorspace that respects the pixel information as much as possible. This allows a lot of creative freedom for the artists that work on our files down the line.

Now that we’re all caught up on why working in RAW is the creative’s galore, we will be sharing our VFX workflows when working with professional video production houses in the next post!

Nicholas Chia

Author Nicholas Chia

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