Wednesday, January 30, 2019

The Color Name Conundrum

This article was flagrantly stolen from my keynote presentation at ISCC/AIC Munsell Conference, July of 2018, and from the ISCC Newsletter of January, 2019.

It’s a common argument that my wife and I have. We are at a store or movie or coffee place, and I will comment on another woman’s blouse. “Hey, Honey. Look at the woman in the turquoise top. Isn’t she cute? … She smiled at me… And she handed me a card with her number on it.” Madelaine will invariably respond with “That’s not turquoise!” She may say that it’s teal, or aqua, or beryl, but she will never agree on the color name that I chose. I can blather on all I want about how I am a world-famous color scientist who was asked to give a keynote for the Munsell Conference. It won’t matter. What do I know about color?

The lady in the allegedly turquoise top

This time, I decided that I would win the argument. I started with Merriam-Webster’s dictionary since it is an authoritative reference that would show I was using the color name correctly. This dictionary defines turquoise as “a bluish-green color”, and follows up with the full and much more explanatory definition “a light greenish blue”.

I exercised due diligence and spoke directly with the person who wrote the full definition, Kory Stamper, to help resolve the argument with my wife. She politely (and wisely) declined to get involved. But I could tell that she was agreeing with me.

[As an aside, the exciting thing about attending ISCC/AIC Munsell conferences is that eminent chromo-lexicographers like Kory might be in the audience when they are called out in a keynote address.] defines turquoise similarly: “a greenish blue or bluish green color”. The Oxford English Dictionary provides a similar definition but leans more to the greenish side: “a greenish-blue color”. So, it seems we have a consensus between the dictionaries. But more importantly, we have a consensus in which I win the argument!
The image below shows blue, greenish-blue, bluish-green, and green. The blouse is definitely close to bluish-green, so turquoise is indeed an appropriate descriptor of the blouse color. Did I mention that I claim victory?

The happy shades between blue and green

But I decided to check one last dictionary, Webster’s Third New International. The definition in this dictionary is at once beautiful and tedious.

1) a variable color averaging a light greenish blue that is deeper and slightly greener than average turquoise blue, and greener and deeper than average aqua or average robin’s-egg blue (sense 1)

My stalwart research assistant suggests that the definition might be a bit too complicated

You can see that our puppy, Mozart, was puzzled when he read it, so I diagrammed the definition out for him (see next image). He thanked me when he saw the diagram, and went off to bark a friendly greeting to a squirrel that was outside. By the way, Mozart is not named for Hank “the Tank” Mozart. You will recall that Tank played defensive hatchback for the Green Bay Bruins. His claim to fame is that he scored the winning basket over Jack Nicklaus in the 1968 War of the Roses Tournament. Madelaine and I named the dog after the less-well-known Wolfgang “Wolfie” Mozart.

An Applied Math Guy reads the dictionary

In most dictionary definitions, the lexicographer works to define complex words in terms of more basic words. The Webster’s Third definition of turquoise is unique in that it defines the color relative to other colors which are just as non-basic as turquoise. To really make sense of this tortuous definition of turquoise, I realized that I had to generate similar diagrams for aqua and robin’s egg blue and turquoise blue and greenish-blue, and then for each of the other colors that were called out in those definitions. It only took me three days to generate the following table that delineates the territory of the ten tones in the turquoise tautology. It is clear from this that color names are very precisely defined.

A handy reference for color names in the blue-green family

But I still wasn’t happy. The intertwined definitions haunted me. Where Kory is the Steinbeck of chromo-lexicography, whoever wrote the lovely and sadistic color definitions from Webster’s Third was the Faulkner. I simply had to find out who this anonymous author was.

Luckily, it didn’t take long. The list in the front of the dictionary of contributing experts provided me with the answer. It had to be Isaac Godlove.

[As an aside, the exciting thing about attending ISCC/AIC Munsell conferences is that the audience will recognize the names of prominent researchers in color when their names are mentioned in a keynote address. Let me tell you, the cheers were deafening! Everyone recognized that Godlove was the third author of the seminal paper “Neutral Value Scales. I. Munsell Neutral Value Scale” from the Journal of the Optical Society of America in 1933.]

Of course, some of the people cheering also recognized that Godlove was the director of the Munsell Research Laboratory from 1926 to 1930. What an enormous coincidence that he should get mentioned in the keynote at the Munsell Conference! A few chromo-historians in the crowd actually knew that Isaac Godlove was the chair of the ISCC Committee on Measurement and Specification in 1933. (Note again the coincidence that the ISCC was one of the organizers of the Munsell Conference!)

While Godlove was chair, a group of pharmacists approached Godlove about the need for a definitive guide to color names. This eventually led to the National Bureau of Standards runaway best seller “Color – Universal Language and Dictionary of Color Names”, which became a Broadway play of much acclaim. This absolutely delightful standard carved the Munsell Color Space into 267 regions (called Centroid Colors) and gave each region an intuitive designator like “bG 159”, along with a euphonious name like brilliant bluish green.

A hue slice from the NBS standard on color names

As if that wasn’t enough to earn a prominent spot in my bookcase, the authors dug through all the available color naming guides (like Maerz and Paul, Plochere, and Ridgway) to determine the Munsell coordinates for each of the color words that were defined. As a result, the NBS standard further provides two lists: 1) a list that goes from common color name to the appropriate Centroid Colors in Munsell space, and 2) a list that provides all the color names that have been associated with each of the 267 Centroid Colors.

I was ecstatic. I quickly saw that this book provided a solution to the recurring argument that I had with my wife. The solution is astoundingly simple. Whenever I am within earshot of Madelaine, I just have to go through four simple steps before I utter any color names.

Step 1: Measure the color in question. For example, I called up the woman in the turquoise top, explained the situation, and met her at Starbucks with my spectrophotometer so I could measure her shirt. She understood my predicament perfectly, and agreed to share a Starbucks with me. Her shirt measured CIELAB of 86, -47, -4. Her name is Teal, by the way.

Yes, it’s a bit of a bother for me to carry a colorimeter with me at all times, but what color scientist worth his or her salt doesn’t carry one for the occasional color measurement emergency?

Step 2: Convert from CIELAB coordinates to Munsell designation. One could make use of the Munsell Renotation Data. The official version is conveniently available on the RIT website to do the approximate conversion, but several people have written software that does this. Harold Van Aken (of Wallkill Color) provided a piece of software as a freebie in honor of the Munsell Color Conference. (Yet another astounding coincidence.) Paul Centore has graciously provided an open source conversion, and Danny Pasquale sells an inexpensive tool called PatchTool that provides this function among others. The CIELAB coordinates of Teal’s allegedly turquoise shirt were thus converted to 5BG 8.5/9 in Munsell notation.

[As an aside, the exciting thing about attending ISCC/AIC conferences is that two of the three people who wrote software for this conversion (Paul and Danny) were actually in the audience for the keynote.]

Step 3: Convert from Munsell designation to Centroid colors. It goes without saying that it is pretty quick and easy to leaf through the diagrams (like the one below) in the NBS standard to find the Centroid corresponding to any Munsell designation. In this case, the Centroid Color is 159. Yes, it’s a bit of a bother to carry the NBS standard with me, but it’s a small price to pay for me to prove that I am right in an argument with my wife.

Step 4: Look up the color names listed under the Color Centroid. In the case of Centroid 159, the list is rather short. It includes Beryl Green, Bewitch, Blue Green, Bluish Green, Bright Aqua, Bright Aqua Green, Bright Emerald Green, Bright Green, Bright Jade Green, Bright Turquoise, Bright Turquoise Green, Chill, Crest, Du Barry Blue, Festival, Green, Ice Boat, Light Emerald Green, Lilting Green, Naid, Persian Green, Picturesque, Pool Green, Promised Land, Salome Blue, Song of Norway, Sprite, Sulfate Green, Turquoise Green, Venetus, Venice Green, … and of course, Turquoise. I win!

The fact that this particular color has 32 valid names shows that our assignment of color names to physical colors is not nearly as precise as Godlove and Webster’s Third would have us believe. We need a system like Munsell or CIELAB (or NCS or RAL or Pantone) in order to accurately communicate colors. That’s an important thing to realize, but the more important takeaway from the research presented here is that I won the argument!

May you enjoy arguing with your significant other as much as I do.

If you enjoyed this article, you might consider joining the Inter-Society Color Council! Individual membership is only $50 per year, for which you will receive the ISCC newsletter, as well as reduced rates for any ISCC sponsored conferences.

Such as... the joint TAGA/ISCC conference in balmy Minneapolis in March.


  1. Dear Jonh. Also when you name a color you should take into account historical names of pigments used in the art paints, since these pigments are spectrally accurate colorants

  2. why is this necessary

    1. This is meant as "edutainment". I apologize if you weren't entertained by the humor and storyline. I also apologize if the history portion of the education was not interesting for you.

      I would hope that the final message found its way into the brains of those involved with color: "We need a system like Munsell or CIELAB (or NCS or RAL or Pantone) in order to accurately communicate colors."

      BTW... send me an email and I would be glad to respond with a large collection of capital letters and punctuation marks. It would appear that you have run out.