Quaternary Hues

2019-12-30

The Quaternary Hues List standardizes names for 24 hues in the RGB color space. Primary, Secondary, and Tertiary colors are well attested historically. This effort is to establish Quaternaries with a greater degree of certainty.

Red 
                         
15°
                         
30°
                         
45°
                         
60°
                         
75°
                         
90°
                         
105°
                         
120°
                         
135°
                         
150°
                         
165°
                         
180°
                         
195°
                         
210°
                         
225°
                         
240°
                         
255°
                         
270°
                         
285°
                         
300°
                         
315°
                         
330°
                         
345°
                         

Rationale For the Quaternary Hues List

I wanted a list of Quaternary colors and was surprised that nothing had been established with confidence. I have found existing lists unsatisfactory. 

I determined to create a fully researched list to answer this question once-and-for-all (at least for myself). Here are some notes on my decision making process.

First, I found available candidates for each hue. Next, I selected the best based on the following criteria:

Quaternary Hex Rings - Missing QuaternariesPrimary and Secondary colors can be established with certainty:

Primaries

Secondaries

Magenta is an extra-spectral color, meaning that it is not a hue associated with monochromatic visible light. Magenta is evoked by light having less power in green wavelengths than in blue/violet and red wavelengths (complements of magenta have wavelength 500–530 nm). An alternate candidate for this color name is Fuchsia, but it is usually considered more purplish than Magenta.

Tertiaries

Tertiaries can be established with near certainty. Additional candidates do not present a serious threat to those selected.

Alternate candidates:

Quaternaries

Quaternaries - High ConfidenceSome Quaternaries can be established with certainty or high confidence. The following are well established and can be considered Certain:

Alternate candidates:

The following can be established with High Confidence:

Alternate candidates

Medium Confidence Quaternaries 

Quaternary Hex Rings Medium ConfidenceThe following can be established with fairly high confidence, though some discretion is involved.

Coquelicot had limited contention for Quaternary 15°. The term was originally a French vernacular name for the wild corn poppy, Papaver rhoeas, which is distinguished by its bright red color, and orange tint. It eventually passed into English usage as the name of a color based upon that of the flower, first recorded in the year 1795. Vermilion, though having a much more recognizable color name, is too red. Persimmon is too orange.

Crimson has some contenders, but due to general use as "a color between Red and Rose," this was the best fit.

Of these, Purple is most ambiguous. The definition of Purple varies by culture, though it has long been used as a Secondary in the RYB color model. At times it has been considered synonymous with Violet. However, it usually occupies a space closer to red.

Lower Confidence Quaternaries

Quaternary Hues Lower ConfidenceThe following were the most difficult Quaternaries to establish, and represent many hours of research to pinpoint suitable representatives.

Royal Blue has a more traditional variation which is darker, which Pantone places at 336° and Mother of All HTML Color Charts at 219°. However, the more modern interpretation is closer to the web color established by the W3C in 1999 which places it at 225°.

There seems to be some agreement that Cerulean belongs here, but I find this unsatisfactory because of the variance I see in the samples. I would place Cerulean at 210° if selecting for a Quaternary. Also, I associate Cerulean with the Winsor & Newton Cerulean Blue oil paint I have used (which it is noticably more Cyanish than 225°). 

Ultramarine The name comes from the Latin ultramarinus, literally "beyond the sea", because the pigment was imported into Europe from mines in Afghanistan by Italian traders during the 14th and 15th centuries.

Indigo's range includes modern-day Blue (240°). In the end, this was a difficult decision and I concede Indigo would have been a reasonable choice for 255°.

Byzantium is a particular dark tone of purple. The first recorded use of byzantium as a color name in English was in 1926. The ISCC-NBS has two listings for Byzantium at 311° and 315°. Because this color could be narrowed down to a small arc, it has been selected over other candidates, which were more difficult to narrow.

There seems to be some agreement that Cerise belongs here, but I would place Cerise at 345° if selecting for a Quaternary because Cerise color examples appear redder than Rose.

Quaternary Hex Rings (labeled)

Cascading Style Sheets

Cardinal Hue Variables

This simple style sheet includes the 24 hues as single-entries:

Color Variations

The variation style sheets include 14 variations built on the cardinal hues: