Once upon a time in physics
Before the age of particle accelerators and radio telescopes, physics was quite tangible.
Issac Newton wrote a book, Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light. The book describes about optics, just as its title says. A famous guy who read the book found that optics isn’t everything of (visible) light for human being. The guy was Johann Wolfgang von Goethe who wrote a book, Theory of Colours (Zur Farbenlehre). It was published in 1810.
Today’s physics is far from tangible. Today we are accustomed to apart tangible things from physics. In 1810, they aren’t. Goethe himself thought he contradicted Newtonian optics. Today, Goethe’s viewpoint looks irrelevant. We accept Goethe’s theory from several different viewpoints: semiology, cultural anthropology, psychophysics, cognitive neuroscience, and cognitive psychology. It is Aristotle-style jumble. Goethe wanted to draw attention to human being, not physical phenomenon. But Newtonian optics isn’t about human being. In 1810, it wasn’t obvious.
Goethe might fail to contradict Newtonian optics, but his critique is rather valid for today’s industrial color science. If he read the articles from the Commission Internationale de l’Eclairage (CIE), he might wrote another book to contradict them. He would never miss to point a fundamental assumption: standard observers.
CIE Standard Observers
The name “standard observer” looks similar to Adolphe Quetelet’s “average man” (l’homme moyen). Today we are familiar to average man. Most industries make their products mostly for average man. So non-average men like NBA players often need special clothes.
No, CIE standard observers are not average man.
Average man sleeps in bed, eats food, goes to walk, and watches TV. Clothes for average man are designed for such life. The clothes work fine (but not excellent) for many of us, undoubtedly.
On the other hand, CIE standard observers are sitting in a dark room from five or ten minutes before (for dark adaptation.) They watch a small light circle, and try to match a half circle’s color to another’s. Average man lives a life. CIE standard observers don’t. A dark room and a small light circle are the whole world for them. They don’t see anything illuminated by the sunlight!
Matured industrial color science is based on CIE standard observers. (advanced academic color science is another story, of course.) It is fundamentally different from clothes for average man. How can we believe such factitious fragmented derivatives work OK in the real world? The answer: the track record in business.
No one became bunkrupt for such industrial color science, whereas quite a few companies become bunkrupt for poor science and/or engeneering. The track record proves the practical value of industrial color science and CIE standard observers.
Ideally, science should find truth independent from business. So industrial color science isn’t a science in a narrow sense. It is an art which works fine in the real world. A humanist, Goethe, has a good reason to blame such inhuman Frankenstein-style art. Sorry Goethe, we are business persons.
Let’s look at the engeneering side of color science, uniform color space (UCS).
Demands and designs of uniform color space (UCS)
An uniform color space (UCS) is a chimera mixing several men who are sitting in a dark room from five or ten minutes before. A man tries to discriminate two colors. Another man tries to match hue of two colors. A CIE standard observer is ingredient, too. Color scientists design UCS for industrial demands, for example, manufacturing tolerance specification.
Newtonian physics came from astronomy because outer space is a hard vacuum which is kind to mathematics. Fluid dynamics is notorious even today. Human perception isn’t a monster like fluid dynamics, but not kind enough to color scientists who design UCS. Physical quantities of color are mathematically simple like Newtonian physics, but we live in the atmosphere.
UCS is designed for industrial demands. These are the most dominant demands:
- Just noticeable difference (for manufacturing tolerance specification)
- Easily recognizable difference (for color coding design)
Easiness of calculation
- Between physical quantities and UCS coordinates
- Color mixing
- Color difference
CIELAB, the most important UCS, abandons intuitive color mixing. CIELUV abandons intuitive saturation.
Modern comuters offer massive calculation capacity for everywhere. Easiness of calculation becomes irrelevant a little. So recent color scientists often propose mind-boggling complex calculations. That aside, UCS is always designed for industrial demands. Different design comes from different demands.
Gamut compression and a technological nepotism
Gamut compression is a relatively new demand.
CIELAB lacks a virtue for gamut compression (hue uniformity), because they are designed before the age of modern computers. But sadly, the designers of ICC profile builders aren’t always keen to such problem. ICC profile for printing is a best friend of CIELAB. So the designers must befriend with CIELAB, and often carelessly adopt it for gamut compression. A technological nepotism.
Zygomatic Color adopts IPT color space for gamut compression. It makes noticeable difference, for example, in deep sky blue. Have you ever felt printed color of deep sky blue is awkward? In most cases, deep sky blue is out-of-gamut for printing, so gamut compression does its job there. It inevitably cuts saturation, but shouldn’t distort hue. CIELAB distorts. Of course, the designer of the ICC profile builder is responsible for that.
Good or bad, (matured industrial) color science is an art. I hope Zygomatic Color makes you happy. Please test it. My design is for your satisfaction, not based on scientific truth.