Designed according to the Munsell Color System, which divides the color wheel into a three-dimensional color-space, shaped like a distorted egg, in which all colors are separated by their chroma, value, and hue. Made using a spectrophotometer to ensure they have graduated steps within a very tight tolerance range. Achromatic, meaning that they have no distinguishable hue or chroma, only value. Use with any one color to produce a monochromatic study. Several colors mixed with the same neutral gray and in the same ratio will produce colors with similar value (depending on the colors own current values).