Chapter 2: Color Theory

Table Of Contents

Introduction

It is fascinating to realize that after fifteen years in the industry I know so little about color. This chapter has been the most difficult to write since I am not a color artist. But hopefully I can still share a bit of knowledge with you.

When you work in lighting, you obviously know some tricks : like orange and blue go well together. This scheme (a combination of colors), called “orange and teal“, is probably the most used in Hollywood. Why that ? I guess that is because it is the most used (and less risky) of all.

They are actually a couple of posts that explain it pretty well. If you understand french, I suggest you read this one as well.

Since we have an Art Department doing Color Keys for us, it is easy for a (lazy) lighting artist to only scratch the surface when it comes to color : just match the reference !

A color key is a concept painting, generally done in Photoshop by the Art Department.

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Pretty good match of the color key, right ? It is not always the case but we will see about this later.

First, let’s have a look at the frames : orange is coming from the fire and blue is coming from the roof. Nice Complementary Scheme ! This scheme is the most used in the Animation Industry nowadays. But there are actually plenty of others schemes available. We will study them below.

Color Terminology

Let’s go back a bit and start from the beginning. I really do not want to copy articles from Wikipedia. So I will just do a quick catch-up on terminology. All the information you need is on the internet ! For example, the Khan Academy of Pixar about Color Science is pretty interesting. To talk about color, we mainly use these three important terms :

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From Sharon Callahan : The eye is more attracted to a color than to a neutral image, the more saturated the color, the more attention it grabs.

In the version 2.0 of this book (release in Q4 2020), I’ll do a proper paragraph about Value, Lightness, Luminance, Brightness and Vibrance.

Color Wheel

How do we organize colors ? Color Wheel is an interesting tool to start working with colors. They are two main different models of mixing colors :

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These are the two most famous models in the industry.

There is no model better than the other one. They just have different uses. Each model has its own Color Wheel, based on Primary, Secondary and Tertiary colors.

There is a third model : RYB (red–yellow–blue, which makes up the primary color triad in a standard artist’s color wheel) described right below.

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I am not very familiar with this model but it shows clearly how a color wheel is built.

The RGB Color Wheel with its additive model is the one used in Computer Graphics. I have done a render in Guerilla Render using 3 spotlights using pure Red, Green and Blue values. We have seen in the previous chapter that our cones are mostly sensitive to these three colors.

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Guerilla Render is based on the RGB model, like most render engines.

I will provide more examples soon (Q4 2020) about limitation of RGB render engines versus spectral render engines.

Spectral rendering can also improve iridescence.

Kelvin Temperature Chart

The use of Color Wheels is also important when it comes to temperature. It is something you will hear quite a lot in lighting dailies : “this is too warm” or “make this light cooler“.

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In most renderers you have access to several color picking options.

Color temperature is conventionally expressed in kelvins, using the symbol K, a unit of measure for absolute temperature. Color temperatures over 5000 K are called “cool colors” (bluish), while lower color temperatures (2700–3000 K) are called “warm colors” (yellowish).

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This Kelvin chart goes from orange to blue… It kind of reminds us something, right ? The “orange and teal” scheme ! When you take an interior photo and adjust your white balance on an artificial lighting, most of the time exterior goes blue. So, yes, “orange and teal” is quite basic but is also very close to natural lighting.

An in-depth look at the Planckian locus

Get ready for some really interesting analysis by some fellow color scientists. Buckle up ! First of all, what is really a blackbody ?

A blackbody itself is a theoretical construct, so by that definition nothing is a true blackbody (no reflected radiation) even blackholes don’t satisfy the formal definition. However, on the other end any object above absolute zero has some blackbody radiation emission, so from that vantage everything is a blackbody… Hence why thermal cameras are helpful to see us human light bulbs in the dark.

Sean Cooper

So blackbodies do not really exist. That’s the first thing !

Another thing to be aware of with black body emission, is that fire emission generally isn’t mainly black body radiation. Lots of light caused by the various molecules making up the fire (this is how fireworks work), so approximating with black body emission is quite limited.

Björn Ottosson

Second thing, fire emission is mostly dependent on what burns. Fascinating !

Pure blackbody is an absolute term, in practice some sources do come very close to being a black body – take a piece of tungsten and run an electrical current through it and place it in a vacuum or an inert gas and you get pretty close, aka an old light bulb. […] Tungsten bulb is pretty much the only light source that is really close, spectrally that is ! You could still find light sources that gets very close from the blackbody locus even though their spectral composition is not at all that of a blackbody, those are metamers.

Kevin Wheatly and Thomas Mansencal

And finally, incandescent light bulbs are the only source that come very close to the Planckian locus, except for metamers. We’ll see about solutions to these limitations right below.

Planckian locus VS Daylight locus

Something worth mentioning is that, contrary to what many diagrams show on the internet (included the one above), 10000K will not give you the “blue sky” colour. It is merely an attempt at classification ! If you have a look at the PxrBlackBody documentation from Renderman, you will see a table that could be misleading :

Temperature ValueSource
15000 to 27000Clear blue poleward sky

There are actually two distinct “datasets” for each locus : Planckian locus and Daylight locus. This article describes them precisely. And since the sky is not an emissive/incandescent body, it is basically impossible for a lighting artist to achieve a blue sky colour by using the Planckian lockus. It is just the wrong dataset.

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Here is a little summary about those two notions (from Wikipedia) :

Some great explanations

I am going to quote a few persons from a conversation we had on the osl-dev list, since their explanation is so brilliant :

Blackbody for lights is for incandescent lights without filters. Anything else and the renderer should allow users to input colors in some other fashion, such as RGB. […] Take a look at this graph which shows how at 700nm the blue star is still outputting more red than the red star.

Thiago Ize.

If you’re using a blackbody for a light colour it should be because you’re trying to simulate an incandescent of that temperature. Blackbody colours have precisely nothing to do with the colour of the sky. As others have mentioned the fact that literature refers to colours as “sky blue” is an attempt at classification.

Anders Langlands.

The blackbody function is good for figuring out the color of something that is purely an emissive warm body, no more and no less. An incandescent filament, a glowing hot piece of metal, molten lava, etc. There’s no particular reason to think this function would give you a good approximation to daylight sky, which is not a blackbody phenomenon.

Larry Gritz.

It could be interesting to implement a function that gives the range of plausible overall daylight colors given a 1D input, a bit like the blackbody_rgb function and the BB_TABLE. It could be called daylight_rgb_function and could rely on data such as CIE D series illuminants. Therefore a lighting artist could reach easily a “blue sky” colour for a rim light.

Complex phenomenons such as Skylight and Fluorescent light sources

In the previous paragraph, I was mostly referring to the color selection process based on Kelvin temperatures that is available in most DCC softwares.

The Physical Sun & Sky (or Skylight) is a much more complex phenomenon to describe. And for the record, it looks like there are 16 CIE Standard General Skies (available in this webapp), which eventually gave birth to the Hosek-Wilkie Sky Dome that has been implemented in most render engines.

There are several computational models that have been published for sky color, and they are usually more complex than merely the raw daylight color temperature — they are a complex function of position on earth, time of day and year, direction, and atmospheric conditions.

Larry Gritz.

Fun fact : the bluest sky in the world was measured in Brazil.

And if we want to push things even further, we could maybe go the extra mile :

Colour temperature as an input by itself is limited because pure blackbodies do not really exist in nature, so you want something that can model correlated colour temperature (CCT). With a tint control (based on CCT/Delta u’v’), you can also model fluorescent light sources & co.

Thomas Mansencal

Kelvin comparison

Is there a better way between working in RGB and Kelvin ? I know that this question is quite controversial. Some studios almost had a holy war about it. In my opinion, it is only a matter of art direction and habits.

The secret life of pets (Director : Chris Renaud, Art Direction : Colin Stimpson) has been almost entirely lit with Kelvin temperatures to get a natural look. This would have been completely impossible on Lego Batman (Director : Chris McKay, Production Designer : Grant Freckelton) because of its saturated yet very original art direction.

Some supervisors prefer to work with Kelvin to avoid unnatural colors. It is like a safety net to them. I personally prefer RGB.

Honestly I don’t blame them.

There is one BIG difference though between these two films : how compositing was used.

  • Pets” mostly got his filmic look in compositing thanks to gamma, color corrector and saturation nodes. And of course 2D motion-blur and depth-of-field.
  • Lego Batman” got his saturated look directly in lighting. I used the craziest values in my lights at Animal. It was almost a cultural shock to me.

I know some people may disagree so let me explain better. I am not saying there was no compositing involved on Lego Batman. But since we rendered with 3D motion-blur and depth-of-field, it was the first time in my life that I could get the final result in my Render View.

More on that later.
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This is actually a huge debate in studios. How close a render should be to the final image ? I personally think that we should be as close as we can to the final render. But we will get to that later.

Color Schemes and Harmonies

Interestingly enough the RYB Color Wheel is the most used for any study of the Color Scheme. It is probably due to the historic use of red, yellow, and blue pigments as primary colors in art and design, particularly painting.

Here is a representation of Color Schemes :

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  • Monochromatic colors are all the colors of a single hue.
  • Analogous colors are groups of three colors that are next to each other on the color wheel.
  • Complementary colors are pairs of colors which, when combined or mixed, cancel each other out by producing a gray scale color like white or black. When placed next to each other, they create the strongest contrast for those two colors and are always opposite on the color wheel.
  • Split-complementary color scheme is a variation of the complementary color scheme. In addition to the base color, it uses the two colors adjacent to its complement. This color scheme has the same strong visual contrast as the complementary color scheme, but has less tension.
  • Triadic Colors that are evenly spaced around the color wheel. Triadic color harmonies tend to be quite vibrant, even if you use pale or unsaturated versions of your hues.
  • Tetradic or Rectangle is a combination of four colors that consist of two sets of complementary colors. These colors form a rectangle on the color wheel. The colors on the short side of the rectangle are spaced one color apart.
  • Square is a combination of four colors equally spaced around the color wheel.

You can find more explanation about color schemes here and from this great slide.

Schemes examples

Some Color Scheme Generators are available here and here. Even Adobe has made one ! They are really fun to play with. I thought it was interesting to have a look at the full list of color schemes because animated feature films mostly use the Complimentary Scheme. It kinda becomes a cliché.

Here is a quick study of the color schemes from Toy Story 4 (Director : Josh Cooley, DP : Jean-Claude Kalache and Patrick Lin). There is a great variety in this movie.

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There is a website with some pretty good color schemes : the vivid theory.

After a few years working on animated feature films for Hollywood, you kind of end up seeing only two colors : Orange and Blue. Like this movie, Coco (Director : Lee Unkrich, DP : Matt Aspbury and Danielle Feinberg) :

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What I really like though is that they change the scheme when introducing this new character Ernesto de la Cruz. The choice of green color is not fortuitous, it makes you feel uncomfortable. Maybe you don’t realize it when watching but your brain is probably like “something is off with this guy.” We will come back to the green color a bit below.

Since we are talking about standardization on a movie, I am going to make a public confession. I have used the same blue color for the past ten years in all of my sky-related lights such as top, rim or environment lights : R : 0.4 / G : 0.7 / B : 1. Same goes for the sun: R: 1 / G: 0.8 / B: 0.6. Yes I only use round values, they are easier to share and to remember.

These are non-ACEScg values by the way.

Color Psychology

The use of colors is certainly not something to take slightly. Each color can have a strong impact on us based on our age, culture or gender. In 1980, Robert Plutchik constructed a diagram of emotions visualizing eight basic emotions : joy, trust, fear, surprise, sadness, disgust, anger and anticipation.

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The sequence from Coco with Ernesto de la Cruz uses pink and green which gives Annoyance and Apprehension. Pretty accurate right ? Interestingly enough, Pixar has inverted the colors of Fear and Disgust for the movie “Inside Out”.

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Here is an explanation on the Character Design :

We relied on some verbal idioms like I feel blue, I feel sad, I’m about to explode with rage, etc.[…] Joy was a star, or a spark. Golden and illuminated. Sadness was a teardrop. So her shape and color resemble a teardrop. Fear is like a raw nerve, just a squiggly line, that’s why he’s tight. Disgust is the shape and color of a stalk of broccoli. And of course anger is a brick, immovable.

This makes sense but I am still not sure why “Fear” is purple though.

Color and Emotions

According to Paul Ekman, emotions are universal. But the way we show them, like our attitude, is cultural. He also says that what triggers the emotion is a personal factor. We can also state that the camera, music and lighting work are mostly addressed to the viewers’ emotions.

But we should be careful to interpret colors as symbols because they are mostly linked to a culture historically and geographically. Let me just quote Sharon Callahan here because I do not want you to think there is a universal color code. It is a bit more complicated than that.

Not until the Renaissance was color appreciated as an aesthetic choice. […] There are enough common life experiences and contexts within which to draw some generalizations about how color affects us emotionally, especially in American culture where many of them have been stereotypically reinforced by advertising.

Color temperature for natural and artificial lighting are quite universal. To deviate from them will most likely provoke a reaction. But nothing says that this reaction will be the same for every culture of viewers.

Perfect example for that is the white color : white being connected to weddings in the Western world but to funerals in China.

In the version 2.0 of this book (release in September 2020), we will detail colors and their emotions in the Western world : Red, green, blue, violet, yellow, orange, brown, pink, black, white and grey.

Bad Guy Syndrome

Personally I have never heard a Lighting Supervisor arbitrarily say something like : “This character is angry. Light him in red.” Most of the time the intention of color comes from the surroundings of the character : time of the day, weather and location chosen by the Art Department.

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A quite common example would be the bad guy standing in front of the chimney. To enhance the drama, a fire is generally an interesting light source. It allows us to justify strong rims or even light coming from below, like Ninjago (Director : Charlie Bean, Cinematography : Craig Welsh) :

We had a pretty accurate color key for this sequence. This is why we mostly focus on the White Balance in lighting. This is our primary concern. We also try to make our images look pleasant to the average viewer : easily readable, saturated, not too dark with a nice shaping and composition.

We will see how to achieve all of this in the next chapters.

Production Examples

I am going to detail here different feature films. Each movie production can be quite unique due to various factors : art direction, size of the company, roles among the team… But let’s not kid ourselves. Most movies are a huge investment and most producers want to play it safe : I have lit the same way and used the same colors on “Planet 51“, “Pets“, “Ninjago” or “The Star“.

Planet 51 and The secret life of pets

Much like Planet 51, The secret life of pets has a naturalistic look. It does not mean we only used natural lights but that the look of the film is natural, as opposed to artificial. We will dive deep in this topic in Chapter 4.

One thing I missed on both movies was the presence of the Art Director (AD) in dailies. In my experience, production is way more interesting when the AD comments the shots directly with us. Since he is the one who painted the color keys, I think it makes sense to have him on board until the Digital Intermediate (DI).

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Naturalistic looks are very common in animated movies.

Playmobil

I had the chance to work directly with Rémi Salmon, Production Designer of Playmobil the movie. Having him on the floor with the lighting crew was really useful : he was often available if I had any doubts or questions. Here is a couple of examples where Rémi used color to reinforce the story.

There is a sequence where two characters disagree and are arguing. How can you use color to translate this visually ? I thought Rémi’s solution was really clever :

We are going to use the garland behind them as a justification for playing some colorful rims. However, Marla’s head will be lit in blue and Del’s in pink. And we will use a gradient to invert those colors on the seats. It is like if each character was in his own bubble.

I really thought this was a great idea. Unfortunately, I can only show you these screen grabs from YouTube but I hope you get the idea :

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Apparently, a similar technique has been used on the movie… Se7en (Director : David Fincher, DP : Darius Khondji) ! Check this article, it is a must-read !

The mismatched investigators examine a cache of revealing notebooks discovered in John Doe’s apartment — conflicting color temperatures adding to the scene’s unease.

Playmobil night sequence

We did another sequence with the same two characters where they land in an hostile city at night. Same challenge here : How do you make the viewer feel their discomfort ? Another great solution by Rémi :

We are not going to make the sky blue. But green. This will show their discomfort. Green is a pretty uncomfortable color.

There was a debate about whether the sky should be blue or green. The blue version was nice but I thought green was more original and served better the story. I am really glad we could stick to this idea. Let’s say that the blue version was the safe one since 90% of CG movies have a blue night. Here is part of the sequence :

Physical but green

I had a debate recently on how to make the sky green in CG. The solution may seem pretty obvious but apparently it is not. Let’s say you are on a technically oriented show and for some dogmatic and/or practical reasons you only want to use a physical skylight. You have two solutions :

  • The green tint of the sequence comes from a grade in compositing. Not ideal at all since you won’t see it in lighting.
  • The green could come from the haze (volumetric effect) by tweaking its color. Not great since the green haze will probably be not part of GI and reflections.

My recommendation would be to put the green color in the environment light. No grade, no complicated setup. I personally like when the sky you see in your render is the one that illuminates the scene. Or you could ask Matte-Painting to deliver an HDR map, we did that a lot on Lego Batman. We will talk about this in Chapter 4.

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It is fun to play with artificial skylights once in a while.

Some supervisors stick only to Physical Skylight to avoid big discrepancies between sequences. It is also the insurance to get a predictable result. But you also lose control. I guess the question is how much control do you want to give to your team ?

The green problem

This theory about green was confirmed to me in this book by James Gurney. It is funny because I read this book when I was working on the sequence above. And I started to connect the dots… Have a look at James’ blog, there is some amazing stuff there.

The Green Problem : In the paperback book field, there’s an old saying that “green covers don’t sell.” Costume designers have told me that green often looks ghastly in stage lighting. Gallery directors have reported that clients aren’t attracted to paintings with a strong greenish cast, especially if the color tends toward a bright yellow-green.

Why did I use Playmobil as my first two examples ? Because On Animation is a pretty small company (around 200 people) and we had the chance to have Rémi on the floor with us and during dailies. That is something we do not see that often unfortunately.

Lego Batman

One more example about the green color. In Lego Batman, there is a sequence where the Joker tricks Batman and offers him a deal. Guess what is the dominant color of the sequence ?

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Having Color Schemes per character is a very powerful tool. It can show their personality and their arc through the story. The Batcave in the slide above is the perfect example of having the same location under different influences : the change of color scheme indicates an important story point.

My personal experience on this movie was different from anything I have ever seen before. For example, we did not use any Color Key. I know this seems insane but this workflow actually makes complete sense. We will come back to that in Chapter 5.

Lego Batman night sequence

Here is an other example on Lego Batman : we were launching a sequence set in the woods at night, and Grant Freckelton was showing me some references. He told me :

We are going to make a sequence where the key will be warm on the set, neutral on the characters and blue on the volumetric FX.

When I heard this, I can tell you that my heart skipped a beat. What the heck ? How can one make this work ? Different colors for the same key ? I just had finished The Secret Life of Pets where we did not use any Light-Linking and barely no cheat… I was not prepared for this !

Use of color On Lego Batman was very original and pretty much insane. It is the only movie where I used these (almost) pure colors : R : 1 / G : 0.01 / B : 0.01. It took me time to accept it as it was so different to what I am used to.

I actually avoid to put 0 in CG, this quite a dangerous value as it completely removes the information. 0 in CG is considered an optimization value.

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After a few days, I realized his choice was just great. The colors work really well together. It is actually a pretty common technique in his work : different colors for geometry and volumetric give depth and readability.

Something important to notice is that we used neutral lights on the characters for the skin tones. A blue light on a Lego figure (or a minion) does not look good ! Damn green !

How to train your dragon

I haven’t worked on this movie but I would like to use this example from Dave Walvoord. Do not hesitate to check his talk from Siggraph 2019. It is a very interesting read ! I think the color principle he is describing below is simple but very clear and efficient.

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Very interesting how the color is linked to the story.

Interesting comment about color in Lighting Design for Stylized Animation : “Using this color theory as a guide for lighting, it means that the Hidden world is lit with mostly neutral lights to allow the local colors to dominate. While in the human world, due to the desaturated local color palette, very saturated lights can be used to give each sequence a distinctive color palette and to enhance its mood.”

I guess on Lego we used saturated lights on already saturated bricks !

I will use Dave Walvoord’s talk several times in my book as a point of a comparison. Stay tuned !

Color and lights

It is difficult to come with some advice on color but here is my two cents. When you light, try not to have overlapping colors since they will just cancel each other.

For example if you light a character, try to have one main hue for the left lights and an other hue for the right ones. Otherwise your render will just blend these colors (additive process) and get all muddy.

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Let’s now have a look at a clear example from Dragon where lights do not cancel each other and their temperature blend perfectly.

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Another great example of naturalistic look, enhanced by dramatic lights.

I am bit overlapping with Chapter 8 about Shot Lighting. The idea is to show that different directions of lights call generally for different colors. This concept is also valid for Set Lighting by the way.

The choice of colors and intensity in your lights is one of your most important task. We generally have a reference to guide us. You should try to avoid the 0 value at all costs. It will remove completely the channel and if you want to tweak your lights later in Nuke, you won’t have any information. Otherwise you could try to render in spectral. Here is an example using a scan by Lee Perry Smith :

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In a way it makes sense : 0 is forbidden in the albedo and it should be in our lights as well. Try to avoid it at all costs !

Concept and Color Keys

It may seem trivial but this is one of the key point of my book/website. Should we apply the same colors and values between a 2D and a 3D image ? What difference is there between the two mediums ? Do we have to match perfectly a color key in CG ?

I completely agree with Dave Walvoord on this topic.

From Lighting Design for Stylized Animation : “First, we use color keys as a guide, not a destination. […] We try not to take our color keys too literally. We want to be open to happy accidents and the process of discovery as we move into 3D.” So true !

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I guess they did not want to match the Color Key because it is a totally different medium. And even if we share some visual principles with 2D and live-action, CG in PBR also has its own rules. The color key above looks great in 2D, but I guess in 3D, there was a lack of details in the grass, shadows were harsh on the faces and they needed more patterns to make the render pleasant.

Color and medium

In my experience matching a 2D color key actually depends on many factors : the relation between the art department and lighting, the director of the movie, the schedule… Some supervisors like to stick to references, some don’t care… It really depends.

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I’ll now use a the short film Competition as an example where the color and the medium were deeply connected. I’ll focus on the first minute. Let’s have a look :

Adapting the color keys to CG was a bit of headache in this short film. The CG artists tried to match as close as they could but something did not quite fit. I personally think it was mainly due to the change of medium. Here is my explanation :

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Here is the key to CG : we need details. And guess what ? Details are expensive. Once again if you are a surfacing artist, do not hesitate to check the PBR guide from Substance. It is a great read on how to add colors and details to a material.

I’ll finish with this quote from a great CG supervisor : each step of the pipeline should be an improvement from the previous step. Layout should be an improvement from storyboard and the same applies for lighting and color keys.

The 2D legacy

What happened on most movies I have worked on ? The director used to be an animation supervisor and the art director is an illustrator with a 2D background. This may cause some issues when reviewing lighting shots.

From Kristof Serrand’s conference : “Many people asks me when I am going to direct a feature film ? That’s a very weird question. It would be like asking Gérard Depardieu when he’s going to direct a movie.”

I have sometimes heard comments on PBR movies such as “Can you remove the Global Illumination ?” or “Can you make the shadows brighter without changing the rest ?“.

There is very often a cultural shock between 2D and 3D and the best solution I know is this one : have a proper Director of Photography (DP) or Lighting Supervisor who is PBR-friendly. Let’s have a look at these photos by Sabine Weiss and concepts by Alberto Mielgo.

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Let me be crystal clear here. I am not saying that 2D is lacking details if you compare to 3D. I am saying that 2D can afford some minimalism (a simple ramp or a brush stroke) that 3D (PBR cartoon) cannot. You may see this in Lou Romano’s work for example. But it does not make one medium better than the other.

On a famous movie produced in Canada, the art director would keep asking for gradients everywhere. Can I have a gradient from the head to the feet ? And one from the foreground to the background ? And one from the left side of the character to the right ?

I let you imagine how the light rigs would look after this kind of comments.

Lego Batman experience

It seems to me there was an interesting solution on Lego Batman for the division of roles :

  • Chris McKay is the director of Lego Batman, taking care of many tasks such as layout, animation, dialogues, editing and storytelling.
  • Grant Freckelton is the Production Designer of Lego Batman taking care of modeling, surfacing, lighting, visual effects and DI.

I personally think this division of labors was really efficient. Each “director” was responsible for what he knew best.

What does this mean concretely ? Chris McKay was not present during lighting dailies. Grant and Craig Welsh were running the show in lighting since they are really good at it. And once a week, they would show the approved shots to Chris. The worst retake I ever had from him was : “There is an important line of dialogue by the end of the shot. Can you make Barbara’s face a bit brighter ?

Grant, our production designer, who would work mainly in Photoshop, actually knew about Global Illumination and our render engine : Glimpse. That’s very rare. I asked him if he was trained. I love his answer.

Just enough to understand the various passes that come out of rendering and the basic principles of shading and lighting. […] Physically based renderers like Glimpse and Vray are much easier to get good results from than many legacy rendering techniques… which means they’re easier for non-technically mind artists to grasp.

You can check Max Liani’s blog here.

So it looks like that PBR will not only benefit CG artists but also Art Directors. With a bit of training (it does not have to be complex) any person with a 2D background should be able to make wonders.

But we do not want the other way around either. If your supervisor is only technical, good luck to you. It is all about finding a good balance between artistic and technical brains.

Two brains

I don’t know if Grant and Craig realize it but they actually solved a BIG issue in animation studios nowadays. On the surface to be a lighter in the VFX industry or in animation studio looks similar. We put lights and render images. But there is one big difference : the culture within the studio. In VFX, lighting TDs are used to match a plate. They talk T-Stop, camera settings and HDR verification.

In animation, we rely on the same principles but we bend the rules. We don’t break them. We bend them. There’s no need to match a plate because we get a concept as an inspiration. It is a more creative process. For Computer Graphics, two cultures have been developed : one mostly artistic and one mostly scientific.

Sharon Calahan : On the other hand, computer generated animation has a more stylized, illustrative quality, with its roots more in hand-drawn animation than live-action cinema.

Let me give you an example : I arrived at Framestore right after Despereaux. A bunch of tools had been developed for this animation movie to help artists on several tasks such as stereo. When the animation branch shut down, developers asked VFX supervisors if they were interested by any of these tools. They replied : “We do not use of this stuff in VFX. We are not interested.” Six months later, Framestore was working on Avatar and the same guy had to redo all his stereo tools. Waste of time and money.

Artist or Technician ?

Nowadays, thanks to path tracing, these two methods are slowly blending. But it is still an issue in many studios. On one side we have artists who talk about colors, composition, shapes and design. On the other side, we have CG supervisors who talk about Specular, Roughness, Light-Linking and Displacement bound. We need these two worlds to communicate and share because they both have to learn from each other.

I once asked a colleague in London : are we artists or technicians ? I still remember his answer : a little bit of both.

The word artisan is a good job description.

The BIG issue we are facing today is about Color Keys. How do we translate a 2D image painted in Photoshop into a PBR 3D medium ? It may sound basic or stupid but believe me, it is a very common issue. How do we succeed in making these two worlds work hand-in-hand ? A VFX supervisor once told me : “We need art directors who are PBR friendly.” And he is a 100% right. This is why Animal’s way is the best solution I have ever seen. It uses the best of both worlds.

I have quite enjoyed the Lego Batman workflow. So I’ll often mention it.

A word from Grant

I also asked Grant about his views on color : “Do you have any process to choose the color schemes ? Is it based on the script, your “guts” or just references you like ?” His answer is pretty astounding.

I wish I had a process ! This is a complicated one because it changes depending on each director. It is a mixture of doing a color script in some situations and guts in the other. It’s also a matter of trying to balance aesthetics (making it look cool) with storytelling (making choices that support the process of conveying information and provoking and emotional response). Some directors are happy with a steady onslaught of ‘cool’…. others are all about clarity or naturalism or whatever. This could be a whole discussion about colour theory… but as someone who never learnt colour theory formally I can say guts can account for a lot of it too. I’m still learning about how to use colour !

I love his honesty. “Still learning”. That’s just awesome !

The mental image

It took me a while to connect the dots on this one but let me explain. It seems to me that the fundamental difference between the 2D guys and the CG guys is about exposure. This is at the core of all our issues in feature animation. And more interestingly this issue can actually be summed up in one image. Pretty cool, right ?

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I asked a great 2D art director and an amazing lighting supervisor the following question : What should we try to reproduce in CG ? The camera or the eye ? They both gave me a different answer :

  • The art director replied : the eye.
  • The lighting supervisor replied : the camera.

Generally a director with a 2D background will aim at our mental image (right image), when a supervisor with a live-action experience will go for the camera exposure (left and center images). The only solution I know is to make a choice. Which vision should we embrace ?

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Beautiful frame. A bright object between two characters ties them together.

From Dave Walvoord : Traditionally, animated films are made as viewed from the eye of a painter because of the 2D origins of animation. The Dragon franchise uses the view from the camera.

They did a bold choice on Dragon.

Most of the movies I have worked on had a mental image photography. I personally call this style filled-saturated (débouché-saturé) so it does not scare the children. The shot below from The secret life of pets (Director : Chris Renaud, Art Director : Colin Stimpson) is a perfect example.

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With a photographic exposure, the sky would be blown-out.

Conclusion

I have tried to express my view on color as a lighting artist. While a detailed overview of color is beyond the scope of this document, there are many articles which introduce color theory in wonderful detail :