What is Color and Where is it?
Index
We all do have firsthand color experience and explaining color should be easy…. So what is color and where is it?
Newton, or it is just physics
The first part of our answer lies with Newton, we probably all learned about his experimentum crucis, a series of experiments, where he was splitting sunlight with prisms.
These experiments concluded that sunlight can be separated in its colored wavelength with a prism through refraction. Those colored beams can not be separated further with another prism refracting the light, or in any other way. The colors can only be changed by mixing them with each other or other colors, they are the most basic components of color, often called monochromatic colors or spectral colors.
So a spectral color is our response to a single or narrow band of wavelength. These spectral colors are the colors of the rainbow, each is a pure hue ranging from violett, blue, green, yellow, orange to red. Those colors are basically forming the boundaries of all our visible colors and are the most pure and saturated colors we can see. We can apparently distinguish nearly 100 spectral colors.
When we mix those spectral colors in different amounts we can produce all the colors we can see. When we mix them in equal amounts, the result is white light.
Seeing Newton’s experiments the first answer to our question is:
Color is in light, without light there is no color.
Probably worth asking what is light in that case, right? So let’s do a quick side step here and look into that.
Interlude, what is light?
There is a quote from Einstein, that I do really like:
For the rest of my life I want to reflect on what Light is.
Albert Einstein
We as artists have to study light, to create good paintings, renderings or comps and I do like that the quote shows a connection between scientists and artists. Often either art or science are influencing each other to advance both fields. Anyway back to the topic…
Light is electromagnetic radiation in the spectrum we can see, also called the visible spectrum. If we can’t see it, it is not light. Sometimes people speak of visible light but that term is really confusing, since the only part of the electromagnetic spectrum we can see is light. Light is always visible.
I like the quote:
Light is the energy that permits us to see.
So light is the reason we see the world around us and the reason we can see color.
As you can see in the graphic below, the visible spectrum is quite a narrow band in the electromagnetic spectrum, between 380nm and 720nm wavelength. Since our vision is low at the extreme ends of the spectrum, generally 400nm to 700nm are considered to be realistic.
Left of the visible spectrum are the shorter wavelengths like ultraviolet radiation, on the right end are longer wavelengths, infrared, microwaves and radio waves.
You can also see the monochromatic colors for each wavelength range, as Newton specified them in his experiments (minus the Indigo which was more a blue, while blue was more a cyan for him). ROYGBIV is a common abbreviation to remember those colors and their order.
The wavelength for the monochromatic colors are:
Red at wavelengths higher than 630nm.
Orange is at wavelengths 590nm-630nm.
Yellow is at wavelengths 560nm-590nm.
Green is at wavelengths 480nm-560nm.
Blue is at wavelengths around 480nm.
Violet is at wavelengths shorter than 450nm.
Photometry is the science that deals with and measures visible light, while Radiometry is measuring the full electromagnetic spectrum, including the visible spectrum. I might write a little more about those later, since they are helpful to understand light measurements and scene linear workflows.
Of course there is more to light but for the sake of color that is good enough, back to Newton and a little more history.
Newton published the conclusions of his experimentum crucis in his book “Opticks”, one of the seminal works on color in color theory.
He did one other really important thing for us artists, he created the first color wheel, by connecting the red and blue end of the spectrum. This is the earliest organization of color, two dimensional here, the color wheel is used in one version or another in every graphics software today.
Goethe, or don’t forget the human
When Newton published his “Opticks”, not everybody was fully on board with his conclusions and especially the “lazy” way some of his peers interpreted his findings.
One of his critics was Johann Wolfgang von Goethe, the famous german “Dichter und Denker”. I am sure many germans have painful memories of having to read his Faust in school, I certainly do, but to go back to the “Pudels Kern”…
Goethe was curious enough to borrow prisms, which were very expensive at that time, to replicate all of Newton’s experiments. After doing all of Newton’s experiments himself, Goethe criticized some of Newton’s findings and added his own insights, publishing a book about it all, because why not. That is the second seminal work in color theory, Goethe’s “Zur Farbenlehre”.
To keep it short here, Goethe’s main point was, color is in light, sure, but Newton completely forgot the human experience and interpretation of it. So there is the human factor to the whole color experience which we can not ignore if we want to describe or specify color. It is not only physics it is also psychophysics, our experience and perception of color.
Oh and of course Goethe did create his own color wheel, that thing really started to become popular.
As you might have noticed Goethe organized the colors in his color wheel with complementary colors opposite to each other. He also assigned qualities to each color, yellow is good, green is useful, blue is mean and so on.
I did find Goethe’s approach to Newton’s experiments very impressive, and honestly the best way to make sure things are what they are and that you do understand them correctly is to try them for yourself. It just needs some prisms and C-Stands (not sure where Newton or Goethe got those from) and most of Newton’s experiments can be replicated more or less easily.
Goethe is surely one of my idols, he was so curious and versatile in his interests and his thirst for knowledge could not be quenched easily.
He made a surprising amount of color observations and experiments in his book and he describes things like afterimages, complementary color experiments and his “Kantenfarben”. Really cool stuff in there highly recommended to skim it at least.
Goethe also showed me clearly that you need to be a good observer to be a good artist.
Summary
Color is a combination of different things, color is in light and color is a human sensation, it depends on psychological phenomena and on our vision.
The visible spectrum of light contains spectral wavelengths which we perceive as monochromatic colors, violet, blue, green, yellow, orange and red. By mixing those monochromatic colors in different amounts we can produce all the colors we can see. Mixing the monochromatic colors in equal amounts results in white light.
This leaves us with two of the three main components in color science, light and the observer (us), the third is objects / materials or color in nature. I am gonna write about color in nature next and follow up with human vision, the observer, right after that.
From there we can check how we were able to describe color with math, which at the end is what we need to put it into computer models.
As always let me know if you have questions, critique or input please, hello@christophschroeer.com.
