The Hitchhiker's Guide to Digital Colour

The step by step guidebook for digital pixel pushers trying to get a firm grasp on colour to get sh*t done…
Welcome pixel hustler! If you are new to this site and seeking digital colour comprehension, you might as well start at Question #1…

12 replies on “The Hitchhiker's Guide to Digital Colour”

Hello there!
This content is Truly wonderful.
I had some muddy understanding of how a color is handled digitally. finding proper, non bullsh*t explanation is quiet a quest.
thanks for the hard work, I hope to read more of it soon.

PS: reading the lasts couple of posts I had cold sweat running down my spine, thinking about how of P3 display would “stretch” sRGB code value instead of using an intermediary transfer function when decoding my favorite cats pictures… is it what is happening??? are we doomed?!?!?

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Welcome Charlie, and thanks for the kind words.

Regarding your horror, you have about nailed it. The good news is that one operating system is properly colour managed. The bad news is that the others are not.

On one operating system, almost all items are managed. On the others, it varies software to software. That means you can indeed expect the sRGB values to simply be blasted out “as is” or wrongly frequently.

And remember, transfer functions only control the intensity of light. They can’t change the chromaticities of the lights, which requires a different form of a transform. In fact, Apple’s Display P3 colour space uses the exact same transfer function as sRGB! So transfer functions along can’t fix things!

It’s great to see folks with enough foundational concepts to arrive at their own inferences. That’s amazing!

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Hello, I just wanted to say that I appreciate your hard work creating Filmic, answering questions on StackExchange and other sites and summing up the knowledge here. You are a hero! 🙂 I have learned a lot using those resources.

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I mean there are a lot of expressions I’m not used to, and I have trouble to distinguish what is really informative. it would be possible to summarize main points?

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It’s barely a three minute read, of which a summary of a summary seems to yield little. There are no assurances of communication across language barriers, sadly.

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By Post Author

Hello! Every time I come back to check info and reread chapters I am instantly reminded of how lucky we are for having this. Thank you so much Troy.

For the past few months I have been reading other books and websites regarding this topic and I believe (I truly hope so) that some of the core concepts are starting to latch on. I have tried my best to follow along the different topics with Houdini and Nuke open to feel it in my own pixels and practically understand how theory is applied. But it is here where I have been stuck for some time: applying all the theory in a Nuke (for example) real workflow. I have been looking into Foundry’s own tutorials on Color Management but they don’t go too in depth.
For this reason I was wondering if you knew any books, sites, videos you could recommend covering how to apply all the knowledge covered here into a software workflow. I have been finding quite hard and labyrinthine to take the step from being able to comprehend the core concepts, understand and house keep OCIO configs and knowing that I am possibly missing something, to actually using them to my advantage in real scenes. Without examples on real cases it is quite complicated to know when I am messing up or when I am hitting the note.

Thanks again. Can’t wait for the next chapter of hg2dc!

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Absolutely flattered that you have found any of this useful.

As you have probably discovered, the amount of reliable information of sufficient utility out in the wild is horrifically buried under layers of nonsense, numbers, and often times blind appeals to authority. Couple that with the fact that every single curious mind comes at the subject from a different vantage, and can stumble or get hung up in unique ways. This makes it incredibly challenging to suggest a single book or resource.

Worse, software largely is a mess. Plenty of things are brain wormed with some of the protocols peddled by the massive studios and corporations, or algorithms that are totally busted up rubbish. None of it works. Most of it is nonsense.

The main thing that one can do to insulate themselves from the confusion miasma is try to build up a nuts and bolts understanding. I’d be so bold as to say drawing a distinguishing idea between a “stimulus”, versus a “colour”, is an absolutely gargantuan step to sniffing out garbage. If we firmly locate the creation, perception, and understanding of colour as something that is generated in the human perceptual system, it allows us to immediately second guess nonsense that juggles numbers around, or treats electromagnetic radiation as colour.

To that end, I can think of perhaps no better singular tome to at least get one thinking in the right direction than Ralph Evans’ “The Perception of Color”. While it can be incredibly expensive to purchase a hard copy, there are rumours of a PDF lurking out in the interwebs.

I would be absolutely remiss to not also link you to Dr. David Briggs’ site http://www.huevaluechroma.com. Not only does Briggs cover things in a very observer-image-author vantage, his work covers very contemporary explorations of many often overlooked concepts. It also helps to expose readers to the various models, as well as practical examples to showcase how incredible some of all of this is.

Those are probably two very good entry points to round out understanding, and from there, it can be easier to lift one out of the quagmire of number fscking.

Remember… literally no one on the planet understands how our vision works! Also remember that a majority of the research up to around 1985, often times funded by Kodak, was done using tools that are eclipsed several thousand times over by the device you are reading this on. Their wisdom came from experience and insightful thought. Keep that in mind when you feel you are getting lost in the catacombs of vision, image formation, and numbers!

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Hello, love the posts. As a spectral rendering enthusiast, I’m curious if you ever plan to talk about spectral renderers at all, even as an aside. Since you mentioned RGB renderers and some of their downsides. Anyways, I look forward to the next post.

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Thanks for the kind words.

Spectral rendering is a fascinating topic, but the more important one has nothing to do with RGB nor spectral rendering. These constructs try to emulate “light transport” to varying degrees, including the somewhat ridiculous idea that a photometric system such as RGB can do so at all given that it is firmly entrenched in photometry.

The much more pressing discussion I hope to stoke the imagination on, is the *output* of these models. No, not the completely underwhelming radiometric or photometric datasets they generate via rendering, but rather how we create pictures using that data as but one ingredient.

The last couple of posts have been slowly inching in that direction, as hopefully folks can see. In traversing this landscape, we also are forced to reconcile some incredibly woeful misinformation or seductive underlying belief structures.

I believe very strongly that a focus on *what a picture is* can help to guide us in our understanding of human cognition, of which visual cognition is but one artificial demarcation facet.

Keep asking the questions. We need more questions.

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