Hue, Value, and Chroma, the Three Dimensions of a Color
How do you describe a color?
When talking about color, there are some terms that in current language are used as synonyms, however, in a more technical language have very different meanings.
In 1905, artist and teacher Albert H. Munsell experienced the confusion from using common color names to describe a color.
- One person maroon is someone else’s burgundy.
- Navy blue may be one of a number of different dark blue colors, as anyone who's tried matching a blue jacket with blue pants knows.
Albert Munsell devoted his life to developing a color identification and notation system that prevents confusion and makes communication easier. To describe a color, there are some attributes that can be specified in mathematical detail and clarify exactly what color you are referring to:
The Three Dimensions of a Color
Name of a color family
Lightness or darkness of a color
Strength or intensity of a color
Color Dimension 1: Hue
You can think of hues as the colors of the rainbow. If we arrange them in a circle, in a sequence from yellow, yellow-red, red, red-purple, …. We end up with a color wheel of the hues.
Each hue includes the different colors that vary in value (dark/light) and chroma (intensity) but are part of the same hue family.
For example, in the blue hue, you can find a wide range of blues. Of course, there will be pure blue, but also light blue and dark blue, intense (high chroma) blue, and dull (low chroma) blue, and all combinations in between.
All Hues Are Colors, Not All Colors Are Hues
While all the hues on the color wheel are also colors, some colors are not hues and are not included in the color wheel.
Think of brown for example. Brown is a color, but it does not appear on the color wheel because it’s not a hue. In fact, brown is a dull color under a hue. Depending on the kind of brown, it could be a dull red, orange, or even purple.
Color Dimension 2: Value and the Munsell Value Scale
Value is the degree of lightness or darkness of a color.
Munsell has divided the gap from black to white in ten equal steps, called the value scale.
Black has value zero, and pure white has value 10, the values in between are gradually lighter grays of values 2, 4, 6, and 8.
Every color can be associated with a specific value. You can see the real value of a color by squinting.
When squinting, your eyelashes filter, and somehow block, the colored light, letting you see the color-less grayish version of an object.
While you squint, you may hold a value scale in the line of vision next to the color you are evaluating. This way it’s easier to compare and determine the exact value.
Color Dimension 3: Chroma
Chroma refers to the strength or intensity of a color. A high chroma color is pure from any presence of gray or white. For example, lemon yellow has a high chroma, while a banana yellow has lower chroma.
Colors with strong chroma are often referred to as bright or saturated, However, the term brightness is also used to describe the intensity of light and, therefore, indicates a combination of value (lightness) and chroma.
Croma is represented by the horizontal scale on Munsell’s color chart in Fig.1
The Color Solid
Because each color has three dimensions, an arrangement of all colors takes a three-dimensional form. The gray scale serves as the center pole, with white at the top and black at the bottom.
- The Munsell color solid cannot take the shape of a perfect sphere because hue families contain different numbers of steps in chroma.
A Visual Representation of the Munsell Color Tree of Hues
The Munsell notation of a color is written as a whole number, followed by a letter and a fraction.
- Hue number and letter designation
- Value number/chroma number
Example: 5R 4/14
- 5 Red
- Value 4
- Chroma 14
- This is a “pure” red, medium dark, and very strong.
Other Interesting Terms and Notes
- A tint is usually intended as a lighter version of a color, obtained adding white to the color.
- Shade: A darker version of a color is usually referred to as shade. Generically speaking, it can be obtained adding black to a hue, even though sometimes the mix may need adjustments because black may change the hue.
- Pigments are particles of colored material that, when suspended in a liquid or a medium, become paint.
- Black is a neutral color that has no chroma.
The New Munsell Student Color Set
Here are some of the topics covered, all on the subject of color:
- How light interacts and changes
- Visible and invisible attributes
- Warm and cool hues
- Advancing and receding colors
- Emotional response
- Additive mixing
- Subtractive mixing
- Combining colors
An amazing book, not a light read, but a great source of information for anyone interested in color theory. If you buy a new copy, you get to manually assemble all the color charts using the provided color swatches. I missed that part of the fun, but I'm happy with the cheaper price tag of a used copy.