:n4 



Life and Lttfent of Francin (ralton 



80 on up to the ninth which wiis all black. On spinning these nine teetotums, 

 he obtained a 'real' scale of tones from white to black'. Having thus ob- 

 tained a scale of nine tones from white to black, Galton terms the fifth of the.se 

 ( 1 so' painte<l black) the medium tone. Pictures painted with tones less tlian, 

 but up to and including, the medium tone he calls 'faint'; pictin-es painted 

 in tones from the medium to the black, he calls 'dark*. He then caused three 

 j)ortrait~s of a lady to be painted with these tones: 



(a) is the normal painting, using all the tones from to 8, i.e. white 

 to black ; 



(b) is the faint painting, using all the tones from to 4, i.e. white to 

 metlium grey ; 



(f) is the dark painting, using all the tones from 4 to 8, i.e. medium 

 grey to black. 



On Plate XLV will be seen Galton's scale and the portraits. Of these he 

 writes: 



"I exhibit ttiifc sketches of tlie siiiiii' portrait to show tlie dirt'croiiocs of effect under these 

 conditionfi, and how very little the mere question of more or less likeness is HfTected by them. 

 All the tones from to 8 were used in painting the first picture. Then a grey mixture that 

 matched the medium grey was made in one corner of a palett« and pure white squeezed out in 

 another. The artist by using mixtures of this grey and white, and nothing else, made the 

 s«-cond picture as a copy of the first. It is evident that its resemblance is not affected by the 

 limitation of the range of tones. The third picture was made on the same principle as the 

 secimd, except that black and medium grey were employed instead of white and medium grey, 

 and here again the re.seniblance to the original is jwrfect. It follows that the value of the 

 analytical process is not much affected by the fact that it is unable to transform, in other words 

 that it cannot produce a transformer, or in still other words that it cannot isolate the differences 

 Iwlween any two portraits, but only those between a light half-toned copy of the one and a 

 dark half t-oned copy of the other. It should be remarked that although the light-toned a and 

 the dark-t<>ned b severally contain one-half of the coniplet* scale of tones, yet the transformer 

 of the light-toned a into the dark-toned b contains the complet*; scale." (pp. 13C-7). 



Galton illustrates the whole process well by showing the steps taken to 

 convert any mosaic of four tones into another mosaic of four different tones. 

 He takes tones 6, 4, 2, 2 for A and 4, 6, 2, 6 for .&: see our scale Plate. 



(3) 



(4) 

 (5) 

 (6) 

 (7) 

 (8) 

 (9) 



pew. a (faint half-time), i.e. (M) 



iwg. a (faint halftone), i.e. (4 — Jyf) 



p*^'*. 6 (faint half-tone) 



darkcm-il pog. b (i.n. po*. b + 4) 



pan. a + ne<i. a (uniform grey) 



neg. a + )X)ii. b (the "transformer") ... 



poi. a + (>»«</. a + po». b), i.e. (3) -f (8) 



(which ia the same oa the darkeoed b, or (6)) 



The greatest difficulty in the above proce.ss is to ensure that positive h 



' Ualtoii carefully distinguishes between the scales of 'real' tones perceived or sense tone* 

 and actinic tonen. (p. 137.) 



