Soil Color Measurement: Munsell Soil Color Charts Vs. the GLOBE Soil Color Book.

Color is a commonly measured soil property during field investigations of soils. Consequently, a soil color book is amongst the equipment carried by almost every field soil scientist. Furthermore, almost all of these soil color books are Munsell Soil Color Charts (X-Rite, 4300 44th St. SE, Grand Rapids, MI 49512, USA), which have been in use for over 50 years to classify soil color in Munsell notation (hue, value, chroma). With the most recent revision in 2009, the Munsell Soil Color Charts have a list price of $198.00. More recently, an alternative collection of color charts has been produced for the Global Learning and Observations to Benefit the Environment (GLOBE) program. The GLOBE Soil Color Book (Visual Color Systems, Inc., PO Box 93, Mountaindale, New York 12763, USA) also contains color standards for Munsell colors commonly identified in field soils. However, the price for the GLOBE Soil Color Book is approximately $50.00. Our objective was to determine if there was a significant difference between the color representations between these two sets of color charts. Using 10 new copies of each brand of color charts, the Munsell hue, value, and chroma was measured for all color chips with a handheld chroma meter. Differences between the expected and measured color were determined using the standard thresholds for soil color contrast (faint, distinct, prominent), such that if the contrast between the expected and measured color was faint, the two colors were considered to be a match. We report results on the effects of book type (Munsell vs. GLOBE) and color (hue, value, and chroma) on measured differences, as well as book-to-book variation.