Color standards, along with hue, value and chroma, are all critical to maintaining consistent color. Materials that have a high gloss finish add additional complexity to color measurements. The general rule for evaluating the gloss of a color sample is that the higher the gloss unit, the darker the color sample will appear. Conversely, the lower the gloss unit, the lighter a sample will appear.
Gloss is a tolerance that may be specified in the Munsell Color Tolerance Set and measured in gloss units that use the angle of measurement and the gloss value (e.g., 60° gloss = 29.8). A 60° geometry is recommended by the American Society for Testing and Materials (ASTM) D523 standard for the general evaluation of gloss.