EarthColors: A New Guide for Soil Color Determination
Wetland Journal , Fall, 1998, Vol. 10, No. 4.
by Patrick C. Garner

BACKGROUND

Four years ago I had a classic disagreement with a regulator. With a dozen people watching us, we stood in a forest in a shallow depression he fiercely believed was within a protected wetland. My analysis, based on repeated checks against my Munsell Soil Color Chart (MacBeth Division of Kollmorgen Instruments Corporation, 1990, 1994), was that the soils at this site were not hydric. He said they were. By the time our emotions began rising, we had dug numerous holes, and were each holding samples from the same horizon up against our individual soil books. Neither of us was willing to budge. His opinion was that the B horizon was a 10YR 3/3 with distinct redox. I agreed with the redox, but my opinion, which I could feel was becoming increasingly rigid, was that the horizon was clearly a 10YR 3/4. Finally, I grabbed his book and compared it against my own: the ped I held was now a 10YR 3/3. Impossible. I shifted back to my book: it was clearly a 10YR 3/4. In silence he took my book and did the identical comparison. Our books were off a full chroma. We looked at each other for a moment. He said, Well, what the hell Everyone began to laugh.

Although we settled our differences that morning using other indicators, I left with a uneasiness which was only quieted several years later when I read an article in this journal entitled, Soil Color Charts: The Rest of the Story (Kunz, 1997). Stephen Kunz describes a remarkable process in which he enlists Munsell itself to run a spectrophotometric analysis of its own charts. Munsell concludes that over a third of its own colors on a new 1994 10YR chart are out of tolerance. On Kunz older 1975 soil book charts, Munsell determines that a full 86% of the chips have become unreliable.

My fears had been confirmed. Clearly, scientific equipment must be reliable and manufactured to high tolerances. Munsells was not. Although the Kunz article was little more than an isolated analysis of a specific, random color chart, his experiences matched my own. I had to wonder how much of the loss of fidelity he identified in the Munsell charts was due to the effect of moisture from soil samples, and how much to the effect of rain and snow on the paper stock. Repeated field use also leaves the books notably stained, hard to clean, and on occasion, with curling chips. Worse, Munsell seems to acknowledge that their production runs are flawed, and informs Kunz that the books are only good for about four years under normal use (normal does not include dropping the books in mud or water, or being left open to extended periods of sun).

Near the end of his article, Kunz mentions a new soil color chart, EarthColors (Color Communications, Inc. 1997) Curious, I ordered an EarthColors  book as an annual meeting giveaway for the Massachusetts Association of Wetland Scientists. Everyone who saw it wanted to have their own. A month or so later I got my own copy, and have now used it hand in hand with my Munsell color book on a variety of wetland sites. The charts are quite dissimilar. The following section is partly a personal reaction, and partly a factual discussion of the two books. Certainly the charts are different enough to warrant a careful examination by any wetland professional who relies on soils for any hydric-related analysis.

A Look at EarthColors and Its Predecessor

As far as I have been able to determine, EarthColors is the first new soil color guide since the Munsell Soil Color Charts were developed in conjunction with the USDA over twenty years ago (Goldstein, 1998). Based on credits in the book itself, EarthColors was developed by Color Communications, Inc., in 1997 with assistance from Dr. Elissa Levine, Soil Scientist at NASA/Goddard Space Flight Center; Dr. Peter Veneman and his staff at the University of Massachusetts; and Robert Engel and Peter Fletcher, USDA, Soil Survey Division (Color Communications, Inc. 1997). Color Communications, Inc., is a worldwide color consultant and manufacturer now based in Chicago, Illinois.

The EarthColors chart is clearly intended to improve upon the Munsell chart , and my first impressions are that this goal has been achieved. For instance, the chips themselves are 3 times larger than comparable Munsell chips, and are printed and mounted on water resistant, non-paper stock. Not only can the books be easily cleaned, the larger chips are mounted in a unique waterfall page design so that any ped can be set against a full inch exposure of chip, versus a inch circular edge on the Munsell system.

The EarthColors book is larger, and the three-ring binder stronger. The charts in my Munsell book frequently come apart, while pages do not fall out of the EarthColors book. The EarthColors book includes all of the standard hues found in the current Munsell, as well as new 5R and 7.5R hues. Munsell includes 84 gleyed colors; EarthColors supplies 52. EarthColors supplies a total of 367 chips, 12% more than Munsells 322. The EarthColors book comes with an excellent field soils manual, including soil horizon and layer designations, redoximorphic descriptions, standard graphic estimations of concentrations/depletions, a textural triangle and soil texture proportions. Munsells chart does not furnish a field guide.

Dimensions and weight vary between the two books. The EarthColors chips are 11/16 x 1 , while the Munsell chips are x 5/8 in size. A tradeoff with the EarthColors enlarged chip size is the larger overall book size: the EarthColors book is 4 x 8 ; Munsells book is 5 3/8 x 7 5/8. Although these dimensions are nominally similar, the EarthColors book is 50% thicker than the Munsell book. Weight increases moderately for EarthColors as well, to about 17 ounces versus 12 ounces for the Munsell book.

As equally important as the color chip size, the EarthColors page stock appears to be truly water resistant, with chips that are effectively waterproof. My EarthColors book has been washed with rain, and smeared with assorted soils, including 10YR 2/1 and 2/2 histosols. The chips have not stained, and the book after cleaning looks almost new. After using the EarthColors book, I now find Munsells persistent use of a soft, almost blotter-like paper stock astounding.

Of course I inevitably compared EarthColors chips to identical Munsell chips, both in the 1990 and 1994 edition Munsell books. I also compared chips in the two Munsell books to each other. As Kunz had found, there were obvious differences between the chips in the Munsell editions, and differences between the latest Munsell charts and the new EarthColors book. The greatest discrepancies between Munsell and EarthColors seemed to fall in the lower values, in hue after hue. Above a value of 5/ the chips rarely varied. Although my comparisons are visual only, the differences were not just in chroma (which varied on some chips by almost a full chroma), but in apparent saturation as well. Indeed, the preface to the EarthColors book states that their chips were specially formulated using more earth-based pigments. Color Communications, the manufacturer of EarthColors, advertises that its chips are matched to within stringent tolerances of nominal notations (Goldstein, 1998). See my comments regarding these claims under Conclusion in this article.

Although acknowledging that without scientific instrumentation any discussion of colors becomes immediately subjective, I found the lower value EarthColors chips to be more vibrant. In addition, the EarthColors chips are all finished with an identical matte surface, while many of the Munsell chips vary from a gloss to a matte finish, creating different visual appearances. Kunz notes the same phenomena regarding the Munsell chips, and states that Munsell technicians prefer the matte chips, but are unable to always meet their own standards with the matte finishes, thus being forced to accept glossy finishes. Apparently, EarthColors has conquered this problem.

CONCLUSION

EarthColors is the most complete and useful soil color product currently on the market. It takes a logical, evolutionary step forward with its increased chip size and water resistant page stock. The uniformity of manufacture and thoughtful EarthColors layout make the older Munsell chart look distinctly dated. The EarthColors book is far more field-friendly, and simply easier to use than its competition. After extensive application of the EarthColors book, I have personally retired my Munsell Soil Color Chart.

Regardless, there are several regulatory and technical issues which seem to elude definitive answer. Although Munsell has issued at least three new versions of its charts since 1975, federal references, when specific, only identify the 1975 edition (U.S. Army Corps of Engineers, 1987). Does that negate use of the newer editions? This becomes a relevant question, particularly when we know that Munsell books over four years old are unreliable, and that the 1975 Munsell edition has now been out-of-print for fifteen years. The EarthColors book is new, and I have encountered no regulatory references to it in my research. In particularly formal or controversial analyses, does one favor one chart manufacturer over another?

Further, the issue of color chip discrepancies which I identify, and which have been previously documented by Stephen Kunz (Kunz, 1997), present a technical dilemma. At this date I have not encountered literature which reports objective measurements of the accuracy of color chips made by any of these firms. We do not know whether the errors are exclusively Munsells, or whether they are common to both firms. The manufacturing tolerances for these chips, regardless of the individual manufacturer, must be consistent and reliable. The shelf-life for the books must be well-known, and stressed in the publishers literature.

At ninety-five dollars a book from either company, most of us will tend to replace the books only after damage or extensive use. If the editions become worthless after measurable periods of exposure to the elements, we will replace them sooner if we have been so informed. But these questions cannot be left unansweredtoo much regulatory resource definition now focuses on the minutiae of soil color. The more controversial sites tend to depend on interpretive particulars, and many of us have seen wetland lines shift from five to 50 feet because a soil was a 3/2, and not a 3/3. Using color books which vary in their manufacturing tolerances by as much as a chroma is simply unacceptable.

At the least, soil and wetland scientists must be cognizant that these color books are not infallible. Ideally, an independent group or laboratory should publish a carefully calibrated color chart key that could be used as a master or a baseline for periodic comparisons to field color books. I would suggest the key be printed to tolerances that would vary no more than 0.25 chroma units. The key could be kept in light-safe storage, and used to establish the so-called freshness of the working books. Lacking such a tool, we must expect the publishers themselves to set these standards, and to consistently reproduce them with every edition. The books should still be periodically examined for accuracy by a nonprofit group or university, with testing results published in widely distributed literature.


REFERENCES:

Color Communications, Inc. 1997. EarthColors Soil Color Book. Color Communications, Chicago, IL.

Goldstein, Jill, Marketing Director of Color Communications, Inc.. June, 1998. Correspondence to the author with product attachments.

Kunz, Stephen. 1997. Soil Color Charts: The Rest of the Story. Wetland Journal. 9 (4):8-12 pp.

MacBeth Division of Kollmorgen Instruments Corp. 1990. Munsell Soil Color Charts, 1990 edition. Baltimore, MD.

MacBeth Division of Kollmorgen Instruments Corp. 1994. Munsell Soil Color Charts , 1994 edition. Baltimore, MD.

U.S. Army Corps of Engineers. 1987. Corps of Engineers Wetlands Delineation Manual. Waterways Experiment Station, Vicksburg, MS.

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