How precise are Munsell color sample meant to be read?
One step in Munsell Chroma is approximately 5 CIELAB units (very approximately). In general , people accept that approximately 1.0 CIELAB unit is a visual threshold (again very approximately and dependent on the color in question). Thus, observers should be able to fairly reliably discriminate about 0.2 Munsell Chroma steps under the best of viewing conditions. So what are the best of viewing conditions? A nice bright daylight booth with fairly large samples set up right next to each other. Now, I’ve seen a few of the Munsell soil books, and generally they are … “soiled.” I would be very surprised if the samples in the real world could be considered precise to much better than one Chroma step. On top of that you need to factor in the varying lighting and observers. Certainly with all those variables there is no way the judgements can be considered precise to 0.1 Chroma step.
