The Munsell Color System
The first essential to the application of the Munsell Color System is a clear understanding of the three dimensions of color. Once the simple logic of these dimensions is grasped, the practical advantages of the Munsell System will be apparent.
The reader should be warned at the outset against that fear of scientific perplexity which is ever present in the lay mind. The three dimensions of color do not involve the mysteries of higher mathematics. There is nothing about them which should not be as easily comprehended by the average reader as the three dimensions of a box, or any other form which can be felt or seen. We have been unaccustomed to regarding color with any sense of order and it is this fact, rather than any complexity inherent in the idea itself, which will be the source of whatever difficulty may be encountered by the reader who faces this conception of color for the first time.
The idea of the three dimensions of color can be expressed thus:
With these three simple directions of measurement well in mind, there need be little confusion for even the least scientific mind in comprehending what is meant by color "measurement." In considering further the qualities of color, which are expressed by these three dimensions known as Hue, Value and Chroma, we will take each one of them separately in the order in which they are written, trusting that having done so we may pass to the subject of color balance or harmony and its application to every day practice, equipped with a clear understanding of how it may be measured and noted.
This first dimension is defined by Albert Munsell as "The quality by which we distinguish one color from another, as a red from a yellow, a green, a blue or a purple." This dimension does not tell us whether the color is dark or light, strong or weak. It merely refers to some point in the spectrum of all colors like we have seen in the reflection of sunlight through a prism. Let us suppose now that we had such a spectrum cast by a prism or a section taken out of a rainbow. We know it to be a scientific fact that it contains every possible Hue Color. These Hue Colors merge one into the other by indistinguishable degrees, but always in a fixed order. Now let us imagine that we have such a spectrum fixed or printed on a band of paper and that it begins at one end with red and going through all possible Hues, it arrives back at red again at the other end. The Color Hues are unevenly divided and they merge one into the other by indistinguishable degrees. While still preserving the order of these Hues, let us divide them into equal steps as we do on a ruler into inches, by selecting certain colors familiar to us in every day use -- red, yellow, green, blue and purple. These we will call the Simple Hues. Between each of them we will make another division where each one merges into the other. These we will call yellow-red, green-yellow, blue-green, purple-blue and red-purple. They will be known as Compound Hues because each of them is compounded of two Simple Hues.*
Thus we shall have 10 divisions upon our band. The reason for this number of divisions will be understood when we come to discuss the question of Color Balance. It presents a sufficient variety of lines for purposes of demonstration and for most practical uses. Now if we bend this band around into a circular hoop so that the red at one end meets and laps over the red at the other end, we have a perfect scale of Hue in the circular form in which we shall always consider it. So it is that when we state the first dimension of a color we are merely referring to its position on this circle of Hues. In writing a color formula, this first dimension is expressed by the initial letter of the Hue - R for red, which is a Simple Hue, and B-G for blue-green, which is a Compound Hue, etc.
These 10 steps being a decimal number, may, of course, be infinitely subdivided and it may frequently happen that a given color does not fall exactly on any one of these 10 divisions of Hue, but somewhere between two of them. Allowance has been made for this by dividing each of the steps of the Simple Hues into 10 further divisions. These 10 subdivisions represent about as fine a variation of Hue as even a trained eye can distinguish and it would be obviously futile, for practical purposes, to carry it further. If we uncurl our band again, in order to better see what we are doing and note these divisions upon it, they will appear in this order:
Reading from right to left, beginning at the left of a Compound Hue, the numerals run from 1 to 10, 5 always marking a Simple Hue and 10 falling always on a Compound Hue. Thus we have a series of numerals denoting any practical step or gradation between one Hue and another. In writing a color formula, of which one of these intermediary Hues is a part, we place the numeral, denoting the position of the Hue on this scale before the letter which stands for the nearest Simple Hue, thus 7 R, 2 Y, etc. If, for example, we wish to write the formula of a color, the Hue of which is neither Red nor Yellow-Red, but about half way between the two, we would write it 7 R or 8 R, depending on whether it was nearer to the Red or to the Yellow-Red.
*In the naming of these steps of Hue, Albert Munsell has wisely adopted a terminology which is commonly understood as referring only to color. He has avoided the use of such terms as orange, pink, violet, etc. which have other meanings and might lead to confusion. What is called orange, for example, he calls yellow-red because it is a mixture of these two Hues.
Continue on to Chapter 2 - Color Value