Painters would benefit quite a lot from this book, as it discusses the mixing method of colours and all examples are paintings. Nevertheless, designers can also enjoy the book as they are introduced to various colour concepts.

“While the book can simply be read as a general guide to color, its value will be most fully realized by those who take the time to do the color assignments. They were developed and tested over a 12-year period at the Rhode Island School of Design with graphic designers, painters, textile designers, illustrators, and weavers”. So if you have time, work on any assignment that you feel interested, I personally like the guessing colour and colour inventory exercises.

And knowledge about Light should be a prerequisite before one starts learning about Color. Some AP Physics videos I watched prior to reading this books are:

Light
Light Absorption, Reflection, and Transmission 
Refraction of Light

Disclaimer: The following extraction of key points in the book intends for personal use only. The content all belongs the author.

1. Seeing Colour

Color is said to be contained within light, but the perception of color takes place in the mind. As waves of light are received in the lens of the eye, they are interpreted by the brain as color.

Colors that seem similar (such as orange and yellow-orange) do so because their wavelengths are nearly the same.

The perception of colored surfaces is caused by the reflection of light from those surfaces to the eye. Lightwaves that are not reflected are not perceived as color.

In relatively unfiltered sunlight, like that seen around noon on a cloudless day, the full spectrum of color frequencies, from infrared to ultraviolet, is present.
At other times, such as early morning or late afternoon, particular colors are filtered out by the atmosphere.

Artificial light is sometimes called reduced-spectrum lighting because it is deficient in some color frequencies found in sunlight.

In an effort to capture the effect of light, Claude Monet​ painted more than 30 canvases depicting Rouen cathedral between 1892 and 1894.

2. Hue, Value and Saturation

All colors possess three distinct, fundamental factors that account for their appearance: hue, value, and saturation.

  • Hue

When we refer to a color on the spectrum by its name, we are referring to its hue. The color spectrum is a continuum of infinite hues, each one having a unique wavelength. The continuum contains recognizable hue zones that shift gradually into each other. Their boundaries are ambiguous, so precise hue identity is particularly difficult to ascertain in those transitional areas. Theoretically, at the heart of every zone is the pure, true version of each hue.

Color shifts within a hue zone are sometimes described in terms of “temperature.” Color temperature is either “cool” or “warm” and is strictly an aspect of hue. Color temperature is also contingent on its surroundings.

  • Value

Value signifies the relative lightness or darkness of a color. Another word for value is luminosity.

The “pure” primary triad exhibits differing degrees of luminosity, yellow being the most luminous or lightest in value of the three. Blue and red are similar in value.

Black and white photography eliminates hue and saturation, leaving only value:

David Hockney, A Bigger Splash, 1967, acrylic on canvas, Tate, London. The image on the right shows only the values of the painting’s colors.

  • Saturation

Saturation refers to the relative purity of a color. The more a color resembles the clear, fully illuminated colors reflected in a prism, the more saturated it is said to be.

It is sometimes difficult for the inexperienced colorist to distinguish saturation from value. To do so, one must learn to perceive the difference between the relative purity of a color and its lightness or darkness (value).

Two more useful terms are tint and shade. A tint is a color lightened by adding white; a shade is a color darkened by adding black.

As with the hue and value continuums, the saturation continuum is too broad and undifferentiated to be useful in envisioning saturation in tandem with hue and value. To make it easier to think about the saturation gamut, we break it down into four distinct levels:

A saturation continuum showing the four named levels of saturation

As with similar relative qualities in the arts, e.g. the difference between piano and pianissimo (quiet and very quiet) in music, the ambiguity that exists in the transition between muted color and chromatic gray in no way compromises the meaning or practicality of the terms.

Muted colors and chromatic grays in the same hue

The perception of inherent light in color is rooted in saturation. Unlike luminosity, it is immeasurable – more a psychological than physical event. It can best be described as an inner glow that a color seems to have in relation to other colors.

Value contrast defines shape boundaries.

Differences in saturation suggest varying amounts of inherent light

  • The Hue/Saturation Color Wheel

The color wheel we use shows divisions of both hue and saturation. Primary, secondary, and tertiary hues are arranged around the circle in even, pie-slice increments. The primary colors are subdivided into narrower co-primary slices

This hue/saturation wheel maintains the value (relative lightness) of each prismatic color as it moves toward the center and loses saturation.

Diagram of the hue/saturation color wheel

  • Traditional Color Schemes

Certain hue combinations have had standard, categorical names attached to them. They are based upon a fixed set of hue relationships, but may include all possible variations in value and saturation. The most common of these are: monochromatic(one hue), analogous (hues that lie adjacent to each other on the color wheel), complementary (two hues opposite each other on the color wheel), and triadic (any three equidistant hues that form an equilateral triangle on the color wheel).

  • Color Range

Another way to look at color combinations is through the lens of color range, i.e. the distribution of color in relation to its full potential for contrast.

A broad hue range, broad value range, and broad saturation range

A narrow hue range, broad value range, and moderate saturation range

A narrow hue range, narrow value range, and narrow range of saturation

  • Manipulating Hue, Value, and Saturation Independently

Hue, value, and saturation are discrete color factors and can be manipulated independently. Sometimes the adjustment of one factor is called for without disturbing the others. Color can be altered through color mixing or by controlling the color’s context through color positioning.

  • Describing Colors

The way we commonly describe a color tells us a lot about how we unconsciously rank hue, value, and saturation. In normal parlance, we tend to give priority to hue, accord secondary recognition to value, and integrate saturation, if at all, as a third consideration.

3. Color Interactions

“In visual perception a color is almost never seen as it really is – as it physically is. This fact makes color the most relative medium in art.” Josef Albers, The Visual Nature of Color

Painters commonly experience the surprise of carefully mixing a color on the palette and then seeing it change when it is placed among other colors in a painting. The appearance of a color is affected by its neighbors, sometimes subtly, sometimes dramatically. This is caused by an aspect of vision that makes a halo effect called an afterimage appear to surround individual shapes of colors and non-colors (black, white, and achromatic grays).

4. Color Harmony

“The word ‘art’ means harmony for me. I never speak of mathematics and never bother with the Spirit. My only science is the choice of impressions that the light in the universe furnishes to my consciousness as an artisan, which I try, by imposing an Order, and Art, an appropriate representative life, to organize”. Robert Delaunay

When we consider color relationships, it is important to transcend ideas we may have about fashion and good taste. It is more productive to think about the qualities of concordance (unity) and discordance (disunity) without passing a value judgment on either. An open understanding of color.

5. Color Research

A good colorist cultivates a taste for discovery in his everyday encounters with the richness of the visual environment. Both natural phenomena and cultural artifacts offer myriad examples of exquisite color and color arrangements.

A good way to assess the color in an image or object you admire is to make an inventory of it. We have devised two approaches to color inventory: proportional and nonproportional.

  • Proportional color inventory

Represents the colors found in a source in a way that also depicts their proportional distribution. This approach is best suited to images that have a somewhat graphic appearance with areas of flat color.

The most efficient way to organize a proportional inventory is with stripes arranged in a rectangle.

  • Non-proportional inventory

Natural and manufactured objects that have innumerable colors can be complex, but they can still provide color inspiration. To assess their color content in a proportional color stripe inventory is difficult; there are just too many colors. Instead, we can make a non-proportional inventory to address these complex visual phenomena.

In a nonproportional inventory, the goal is not to record every color we see, but to summarize what we see with a limited number of tones that represent the colors and their range.

6. Symbol and Analogy

Although color has a psychological impact upon us, it can be highly idiosyncratic, especially when it comes to personal color preferences and associations. Indeed, those preferences and associations may evolve over the lifetime of a single individual. Aspects of color experience are also bound by culture to some extent, and can be specific to a particular location or era. Therefore, generalities about what colors signify or how certain colors make us feel should be viewed with a degree of uncertainty.

  • Color Symbolism

When a color is used to signify an abstract idea or represent a belief, it functions as a symbol. The color blue, for example, can signify loyalty as in“true blue,” or melancholy (the “blues”). Red can mean loss of profit (“in the red”) or indicate illicit sexual activity (the “Scarlet Letter”). Purple can signify royalty, but also dramatic excess as in “purple prose.”

Symbolism is generally not the result of a spontaneous psychological response to observed color, but rather a learned connection bound by time and place. In the West, for example, yellow can signify cowardice. In 14th-century Japan, however, warriors wore a yellow chrysanthemum as a pledge of their courage.

Color symbolism is almost always based upon pure hues as seen on the spectrum and typically involves a single color. There are, however, several examples of simple color combinations that have symbolic meanings. Certain holidays in North America are associated with symbolic color pairs: red and green with Christmas, orange and black with Halloween, and purple and yellow with Easter. Tricolor combinations linked with nationality are usually derived from flag designs.

  • Color Analogues

There are certain hues and hue relationships commonly associated with specific psychological responses that seem more intuitively based than the symbolic color interpretations

Unlike color symbolism, analogy is not experienced as a literary phenomenon, but as the direct result of observation. In these instances, colors, which are strictly visual, are unconsciously interpreted as analogues for other, sometimes nonvisual experiences. They are felt, not thought.

The equation of blue, green, and violet with coolness probably has its roots in our long-standing elemental relationship with ice, shadows, and deep water. Conversely, linking red, orange, and yellow with warmth reflects our historic relationship with fire, the sun, and the desert.

7. Color Studies On The Computer

Despite its usefulness as an addendum to the color pedagogy presented in this book, digital studies cannot take the place of working in reflected light with real materials. Some may argue this point, but consider the fundamental fact that, in a sense, the computer screen presents color with a light behind it. Unlike colors that we see by virtue of reflected light, colors on the screen appear disembodied, as if in a vacuum. Moreover, when you stare into a “backlit” color for a length of time; your eyes lose some of their ability to discern fine distinctions due to visual fatigue. While not so extreme, it is a bit like staring into a light bulb.

In digital programs, two different sets of primary colors come into play: RGB (red, green, and blue) and CMYK (cyan, magenta, yellow, and black). These two distinct systems represent the two modes of color application: light and pigment

In additive color, the overlapping of the three primary colors (RGB) produces a white light

In subtractive color, the mixture of the three primary colors (CMY or blue, red, and yellow) produces a dark chromatic gray

The range of colors visually available in any system is called a gamut. The largest gamut is that of the colors we observe in the real world. Colors on a computer monitor are, in all modes, more limited in number than those in the visible spectrum.

An illustration of three color gamuts. The visible spectrum is represented by the large, solid shape, RGB by the pink triangle, and CMYK by the area bound in yellow