Colour Ranges

Dec 16th, 2011 | | Colour Ranges | 2 Comments

Ridgway Color Standards and Color Nomenclature

Ridgway Frontispiece

Robert Ridgway was an American ornithologist, who was the first full-time curator of birds at the United States National Museum. He served from 1880 until his death in 1929. Ridgway also published one of the first and most important colour systems for bird identification, with his 1886 book A Nomenclature of Colors for Naturalists. In 1912 he self-published a larger work on colour nomenclature – Color Standards and Color Nomenclature and it is this work that is featured here.

The purpose of the work was the standardisation of colours and colour nomenclature, so that naturalists, or others, who “might have occasion to write or speak of colours might do so with the certainty that there need be no question as to what particular tint, shade or degree of greyness was meant.”

Robert Ridgway

Robert Ridgway

As Ridgway went on to say in the Preface:

“Many works on the subject of color have been published, but most of them are purely technical, and pertain to the physics of color, the painter’s needs, or to some particular art or industry alone, or in other ways are unsuited for the use of the zoologist, the botanist, the pathologist, or the mineralogist; and the comparatively few works on color intended specially for naturalists have all failed to meet the requirements, either because of an insufficient number of color samples, lack of names or other means of easy identification or designation, or faulty selection and classification of the colors chosen for illustration.”

Ridgway Plate XII

Plate XII showing the hues Rhodamine Purple, Tyrian Rose and Rose Red in the centre

The work consisted of an introduction, with clear definitions of colour terminology, a breakdown of the components in the hues and tones and an alphabetical list of the 1115 colours represented on the fifty-three coloured plates which made up the bulk of the work.

The plates showed a gradual change of hue, step by step, from…
red through orange-red and red-orange to orange;
orange through yellow-orange and orange-yellow to yellow;
yellow through green-yellow and yellow-green to green;
green through blue-green and green-blue to blue;
blue through violet-blue and blue-violet to violet;
and violet through red-violet and violet-red to red…
- the starting point – with intermediate connecting hues.

We are told that for pictorial reasons thirty-six is the practicable number of segments in the ideal chromatic circle. However, these colours are not evenly spaced – furthermore, the number of intermediates required on either side of orange are different, being four in the red-orange series to five in the orange-yellow. Similarly six are required for the violet-red series, while four will suffice for the blue-violet hues.

At the time of writing one of the best ways of establishing the proportion of one colour to another, and thus allowing for its accurate reproduction, was to use a Maxwell Disk. This consisted of interlocking cardboard disks of different colours with a scaled graduated circle of 100 segments around the disk. When rotated the colours merged and different colours could be produced by altering the amount of each one displayed. Once the required colour was produced the proportions of each component could then be read off on the scale.

James Clerk Maxwell holding a Maxwell Disk
James Clerk Maxwell holding a Maxwell Disk 1855
Courtesy of the Master and Fellows of Trinity College, University of Cambridge.

In the example of a Maxwell Disk above, samples of red, green and violet are interlocked and adjusted so that they present, respectively 32, 42 and 26 per cent of the circumference. Superimposed on these is a single smaller disk of neutral grey, and on this two still smaller disks of black and white, the former occupying 79 and the latter 21 per cent of the area. The result of this combination of colours, when the disks are rapidly rotated is that the whole surface becomes a uniform neutral grey precisely like the middle disk.

With the Spectrum colours as a base Ridgway mixed a number of fixed colours in definite percentages. In this way he could produce a series of named colours that could be duplicated at any time. This was important because he had learnt with his earlier work that colours tended to fade.

Ridgway Spectrum Blue
Spectrum blue is shown marked

The first series of Plates (I-XII) showed the pure, full spectrum colours and intermediate hues on the middle horizontal line, each with its vertical scale of tints upwards and shades downwards. The remaining plates show these same thirty-six colours or hues in exactly the same order but dulled by the admixture of neutral grey – the first series (Plates XIII-XXVI) containing 32 per cent of neutral grey; the second (Plates XXVII-XXXVIII) 58 per cent; the third (Plates XXXIX-XLIV) 77 per cent, and the fourth (Plates XLV-L) 90 per cent. The last three plates (Plates LI-LIII) show the six spectrum colours still further dulled by the admixture of 95.5 per cent of neutral grey.

Ridgway’s Color Standards… was published in an edition of 5000 copies by A. Hoen and Co. of Baltimore, Maryland. To ensure uniformity each colour was produced in sufficient quantity for the entire edition. At once it came into general use not only among naturalists but also among florists, manufacturers of paints, chemicals, wallpapers and a variety of other industries.

Ridgway Plate III
Plate III showing the hues Cadmium Orange, Orange and Cadmium Yellow in the centre

Ridgway commented on the constant misuse of terms relating to colour and offered clear definitions for each. In brief these were:

The term that covers the entire range of “chromatic manifestation” – the Spectrum colours – being red, orange, yellow, green, blue and violet (together with those between violet and red, not shown in the spectrum). Spectrum blue is shown in the above plate.

Those lying between any contiguous pair of Spectrum colours – for example “an orange hue of red” or “a yellow hue of orange”. Two hues of Spectrum blue can be seen in the above plate.

Any colour weakened by the addition of white. Four tints of Spectrum blue can be seen in the above plate.

Any colour darkened by the addition of black. Four shades of Spectrum blue can be seen in the above plate.

Each step in a colour scale is a tone of that colour. Each of the coloured samples in the vertical scales of the plates in the book represent a separate tone of that colour.

Colour Scale
A linear series of colours showing a gradual transition from one to another or a similar series of tones of one colour. The first is a chromatic scale (or scale of colours and hues) and in the plates in Ridgway’s book is represented by each horizontal series. The second is a tone scale, which is shown on each plate running vertically from the centre, to a pale tint at the top and a dark shade at the bottom.

Ridgway Plate XLVII
Plate XLVII showing the hues Vetiver Green, Sage Green and Artemisia Green in the centre

As with many who work with colour in a serious capacity, Ridgway had strong views on the naming of colours:

“For obvious reasons it has, of course, been necessary to ignore many trade names, through which the popular nomenclature of colors has become involved in really chaotic confusion rendered more confounded by the continual coinage of new names, many of them synonymous and most of them vague and variable in their application. Most of them are invented, apparently without care or judgement, by the dyer or manufacturer of fabrics, and are as capricious in their meaning as in their origin; for example: Such fanciful names as “zulu”, “serpent green”, “baby blue”, “new old rose”, “London smoke”, etc., and such nonsensical names as “ashes of roses” and “elephant’s breath”. An inspection of the sample books of manufacturers of fancy goods (such as embroidery silks and crewels, ribbons, velvets, and other dress- and upholstery-goods) is sufficient not only to illustrate the above observations, but to show also the absolute want of system or classification and the general unavailability of these trade names for adoption in a practical color nomenclature. This is very unfortunate, since many of these trade names have the merit of brevity and euphony and lack only the quality of stability.”

How interesting to see many of the same old names being trotted out by certain modern manufacturers.

Bald Eagle by Dr. Robert Ridgway

Bald Eagle Haliaeetus leucocephalus, Robert Ridgway, Hawks and Owls, US Department of Agriculture, 1893. Ridgway wrote and illustrated many books and articles on North American birds, along with works emphasising regional birds, including the birds of his native Illinois.

Amongst the many works that he employed to assist him with the naming of the colours were others that have been covered here – Werner’s Nomenclature of Colours; Hay’s Nomenclature of Colours and the Repertoire des Couleurs produced by the French Chrysanthemum Society.

Current Availability of Colours
As with almost all the colours shown on this site those shown here could be mixed into conventional modern paint by Papers and Paints Ltd

Papers and Paints can be found here:

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Comments (2)

rayees ahmadNo Gravatar » 02. Nov, 2013

Is their any option for downloading the all colour plates. Kindly help in the matter

PatrickNo Gravatar » 02. Nov, 2013

I’m afraid not. The book is too tightly bound to scan all the pages.