Recap, Reviews, Video

Codex introduces ColorSynth and the Keys control surface, an entirely new colour grading system

Codex creates digital production workflow tools for independent films, motion pictures, commercials, and TV productions. Within some 30 days after NAB, it will be shipping ColorSynth, a layered colour grading plug-in the Indie market can afford, and Keys, a control surface priced equally affordable.

The first version of ColorSynth will work with Final Cut Pro X, but versions for other NLEs such as Premiere Pro and Resolve will be released soon after. ColorSynth was developed in consultation with Yvan Lucas, a renowned film colourist who has graded over 190 movies, of which many turned out to be blockbusters. The interface was designed with the knowledge he accumulated in mind.

An interview and demo of an hour with Philippe Panzini, VP User Experience at Codex was one of the most interesting we’ve had in years. Before he became VP at Codex, mr Panzini was a co-founder and CTO at Discreet Logic where he worked on Flame and Inferno and he worked for five years at Apple. At Apple mr Panzini helped developing Final Cut Pro X, Motion and Shake.

A major reason for developing ColorSynth was that most of the existing colour grading systems use mathematical models that were fine when we were still dealing with composite video, but which are meaningless with today’s cameras and workflows. According to mr Panzini, those obsolete models were copied to many of today’s systems without a thorough understanding of the underlying math or their genesis.


One of the problems with most colour grading systems is the inappropriate use of the HSL/HSV colour model for mathematical transforms. Mr Panzini said the maths needed to manipulate RGB data but using the common methods that involve HSL, don’t always allow for proper transforms. That is because HSL has been created for selecting colours in a human interface, not for processing them.

The example he gave is the use of the HSL model to remap colours using curves. Using these curves easily breaks the image. The further away you go from the original colour, the more artefacts you introduce.

It took Codex two veteran engineers working for six months to develop the correct mathematical function, despite the company being privy to the maths used in high-end cameras and having a lot of colour science knowledge from its design of circuits for cameras and recording devices. The use of the acronym “HSL” in ColorSynth, therefore, is purely UI and meant only to make users understand what they’re doing. The mathematics behind it is utterly unique.

Although it is simple enough for a novice or casual user, beneath the surface, ColorSynth is an elaborate pre-wired network of colour processing nodes, totalling more than 400 parameters spread over 60 items arranged in an eight-layer stack with several sublayers. Regardless of the complexity of the grade, ColorSynth renders the results in floating point precision, at a near-constant rendering speed, in both SDR and HDR.

Mr Panzini explained that, right now, most people share their work using a bit of CDL and lots of LUTs, but the latter aren’t procedural functions so there’s only as much precision and flexibility you can get out of that sharing mechanism. ColorSynth, however, allows users to share the entire set of grading decisions. Beyond the usefulness of CDL, it allows the entire grading workflow to be shared in a parametric fashion. ColorSynth will evolve to a system where you will be able to share your grading decisions with password-locked individual nodes where required.

Unique features in ColorSynth

Due to it processing colour differently, ColorSynth has unique features, including the Color EQ that allows users to achieve effects not possible with other systems, a Shadows-Midtones-Highlights layer where the transition points are cleanly implemented and user adjustable. And a Selections layer includes an advanced chroma keyer with a very simple UI, granular control through the use of sub-selections and clean linear masks that preserve the subtleness of the gradients in the colour you select.

Finally, there are details that will especially appeal to professional graders, such as the Tone Curve’s mathematical basis that prevents banding and the ability to define S-curves that are adjustable in such a way that you stay in control of the overall brightness of the image, even when you’re changing contrast.

Codex plans to expand ColorSynth’s presence to OFX hosts such as Da Vinci Resolve, but also to 3D animation applications like Maya.

For some images of the ColorSynth environment in Final Cut Pro X, you can visit this page where I have grouped them together.


In its present pre-release state, ColorSynth already has bindings with keys on a typing keyboard and Panzini claims the experience with a keyboard-mouse combination is quite comfortable, but for serious finishing, the Keys control surface will offer a better and faster heads-up experience.

The Keys control surface seems to have been an idea of the CEO of the company. It looks like a keyboard with a large colour LCD panel at the centre. There are potentiometers and keys for navigation and controls. The keyboard’s LCD “follows” the ColorSynth panels you’re using at any time. Keys is bus-powered.