The art of Colour Rendering

Written by Phil Rhodes

Keira Knightley graded by Stefan SonnenfeldMaking the Grade

RedShark Replay: Human beings come in a variety of exciting colours. Rendering those colours in a pleasing way has been a goal of photography since before photography actually had colours, but it's always going to be an incredibly subjective issue

Talk to anyone about the performance of a piece of filmmaking technology for long enough and the conversation will inevitably turn to whether it makes person-flesh look nice in the opinion of the commenter. Whether the topic of conversation concerns lighting instruments, lenses, sensor technology, compression codecs or grading, the subject of making humans look like humans is often discussed as if there's some sort of absolute answer, and the achievement of that absolute answer is why we should pay more money to camera manufacturers and colourists.

No Absolute Answer

But there isn't any such answer. Let's consider two different pictures of a girl in an action movie:

 

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Above: Kate Beckinsale in Total Recall, looking as if there's plenty of blood pumping around her veins. Total Recall was graded by Colin Brown.

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Above: Kate Beckinsale in Underworld, looking like a thirsty vampire, as graded by digital intermediate colourist Jet Omoshebi.

Now, there's no implication that this variation is in any way unintentional; Underworld was made at a time when a cool, bluish and desaturated look was popular for action movies in general, and works nicely with the grim emotional tone of the piece. It also helps Kate look suitably vampiric, given that the actual on-set look wasn't nearly so pale. The point is, though, that practically anything can be justified in subjective terms, and the endless debate about skin-tone is turning the subject into a tyranny in which authority figures get to tell everyone else what their opinion should be. I mean, seriously: put an eyedropper on Kate in the Underworld shot, and she's practically pale magenta, but it's well known as an example of an extreme choice in colour grading making for a popular and successful movie (it made $96 million on a $22 million budget, which is a success in anyone's terms).

 

 

 

 

 

 

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Above: Keira Knightley showing off her canary-yellow skin and a new hair styling technique called “green-lights” in Domino, graded by Stefan Sonnenfeld at Company 3, but also relying heavily on photochemical techniques including the use of reversal and cross-processed film.

Visual Acclimatisation

The only reason the look of either Domino or Underworld in any way acceptable is because the human visual system is so easily acclimatised to different situations, even while the viewer maintains an awareness, unconsciously, of the characteristics of the image, and uses both pieces of information when developing an emotional response. In Underworld, the rest of the shot is very blue, and the skin tone is comparatively redder. It's no surprise to learn that the human visual system is just another of our sense which operates mainly in a relative, rather than absolute sense. But the viewer also remains aware of the overall coldness, in a more absolute sense, and interprets the image and the film in that context.

This quirk of our eyes and brains is presumably an evolutionary development which allows us to judge how healthy people look, or how appetising food is, in various lighting conditions, and it's for these reasons that a colour reference – usually grey – is often provided around grading displays, as we discovered in a recent article by Craig Leedham.

Respect the Colourist

Subjective or not, colourists get a lot of respect, and that's probably justified inasmuch as the standard for consistency and the expectation for colour to play a prominent role in influencing
audience psychology has never been higher. On the other hand, it's important to recognise that there is a huge amount of opinion and taste involved; there is nothing intrinsically right about the look of Underworld any more than there's anything right about the green of The Matrix or the vivid fake-tan orange of any Michael Bay movie you care to mention. There's nothing wrong with any of that, and ultimately almost anything can be justified, with trivial exceptions, given the right circumstances. So, I'm not here to encourage slapdash photography or grading, or to tell anyone not to worry about making the leading lady look alive rather than recently deceased, but the idea that there's some sort of universal standard for how skin should look is no more accurate than the idea that there is any standard for human skin colour in the first place.

 

 

Tags: Post & VFX

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