the actual composition of the greys which are situated upon the Grey axis. Letter a c e g i I n p White 89 56 35 22 14 8.9 5.6 3.5 Black 11 44 65 78 86 91.1 94.4 96.5 You will see that these columns added together give - the first column c =o, w 89, b 11, thus giving o +89 11 100 (theconstant). Ideal hues are not possible commerciallyso we work in the main with the na circle for even the pa circle is difficult to obtain. So artists working in Ostwald colours work in the na circle, which is the circle of values just inside the pa circle. Each Ostwald standard hue is identified by a number, and since there are twenty-four hues in the Chromatic Circle, these numbers range from 1 to 24. But because of economy the basis of the practical work in Ostwald is a range of eight standard hues taken at equal distances from the 24 circle. These eight selected standards are yellow 2orange 5red 8purple 11blue (14), turquoise, a green blue 17), seagreen (20) and leafgreen, a yellow green (23). The numerals given in brackets after the colour names denote the position upon the 24 Circle occupied by these selected hues. a b d e S 9 h k L m n These eight Ostwald standard hues, together with three greys (the neutrals) (a), (g) and form the basis of our practical work. The circle of eight hues gives four pairs of aesthetic opposites. The three greys (a), (g) and (n) can be expanded to a range of five by quantitive mixtures (a) added to (g) gives grey (d) and (g) added to (n) gives grey (k), but in the main, unless you are engaged upon very delicate work, then you will not require either grey (d) or grey (A). Given the eight standard hues and the three neutrals work becomes possible immediately and opens up scope for accurate and balanced harmonies which fall conveniently into four groups. athe Harmony of Opposites (b) the Analogous Harmonies (c) the Dominant or monochromatic harmonies (d) the Grey Harmonies (The Neutrals) But artists like to have the full circle sometimes and so to get the intermediate sixteen hues, that is those hues which lie between the Standard Eight, two between each standard hue, one mixes carefully the adjacent standards and then matches the resultant hues with The Ostwald Colour Album. This Album contains the 680 gradations of colour so smooth, so fine and so beautiful, that one can look long at it until one forgets, ~- 100 or a constant. So c w b 1 for in the case of A SECTION OF THE OSTWALD SOLID The above Diagram shows a principal section of the standardised Ostwald Cclour Solid, containing two triangles of Complementary Hues. Colours in the rows running parallel to the upper sides of the Triangles are ISOTONES and contain the same amount of Black. Those in the rows parallel to the lower sides are ISOTINTS, and contain the same amount of White. The vertical rows are the SHADOW SERIES, where the ratio of Full Colour to White is always the same (as in Nature). In the Grey Series on the Axis each Colour contains a definite percentage of White and Black, as per Table below. The percentage composition of any one of the 28 Chromatic Colours in each Triangle is found by taking the amount of White corresponding to its first letter and of Black to its second letter. These subtracted from 100 give the percentage of Full Colour. Letter C L White 89 71 56 45 35 28 22 18 14 11 8-9 71 5-6 Black a 29 44 55 65 72 78 82 86 89 911 92-9 94-4 Reproduced by kind permission of Winsor Nezcton, Ltd. Gl

Industrial Arts en | 1936 | | page 71