ON DRAWING, WRITING, AND MEASURING. 73 



principal inconvenience attending them is their want of adhesion to the 

 paper : the paper must therefore not be too smooth.* 



For drawings washed in light and shade only, the material's employed 

 are Indian ink, the black liquor of the cuttle fish, or bistre which is ex- 

 tracted from soot : both these last produce a browner and richer tint than 

 the Indian ink.t In using these washes, as well as water colours, there is 

 a great diversity in the methods of different artists : some work with a dry 

 pencil, others with a full one : some begin all their coloured drawings in 

 black only, others use colours from the beginning. When a full pencil is 

 used, care must be taken that no part of the same tint dry sooner or later 

 than the rest. When body colours are employed, there is less difficulty in 

 producing a uniformity of tint than with water colours, each coat of the 

 colour being laid on in sufficient quantity to cover all that is below it without 

 mixing : hence it becomes easier to make any alterations that may be re- 

 quired. For water colours of all descriptions a certain quantity of gum is 

 used, and sometimes a size made of isinglass with a little sugar candy. Body 

 colours contain less gum than other water colours. : Besides paper, wood, 

 silk and cotton velvet are sometimes used for drawings in water colours. 



In miniatures, the most delicate tints are laid on in points with simple 

 water colours; but for the draperies body colours are sometimes used. 

 They are commonly executed on ivory. 



For painting in distemper the colours are mixed with a size made by 

 boiling shreds of untanned leather or of parchment, for several hours : this 

 method is chiefly employed for colouring walls or paper, but sometimes for 

 painting on cloth. For delicate purposes, the size may be made with 

 isinglass. 



When a wall or ceiling is painted in fresco, the rough coat of the plaster 

 is covered with a coat of fine sand and lime as far as it can be painted before 

 it is dry, the colours being partly imbibed by this coat, and thus becoming 

 durable. When they have been once laid on, no alteration can be made, 

 without taking off the last coat of plaster, and each part must be completed 

 at once ; it is therefore always necessary to have a finished drawing for a 

 copy ; this is usually executed on paper, and is called a cartoon. The 

 colours can be only of earths or metallic oxids ; they are prepared as for 

 painting in distemper. The only paintings of the ancients, which have 

 been preserved, were executed in fresco. 



The art of painting in oil was first discovered by Van Eyck of Bruges, 

 towards the end of the 14th century : it has now become almost the only 

 manner in which paintings of magnitude are performed. The colours are 

 mixed with linseed or nut oil, and sometimes with oil of poppy seed, together 

 with a small portion of oil of turpentine to assist in drying them, and with 



* Russel on Painting in Crayons, 4to. Encyclop. Meth. Arts et Metiers vi. Art. 

 Pastel. Contes Crayons, Ann. de Chimie, xx. 370. Lomet, ibid. xxx. 284. Nich. 

 Jour. iii. 216. 



f Gill on Indian Ink, Ph. Mag. xvii. 210. 



% t Handmaid to the Arts, 1758, Field's Chromatography. Mrs. Callcott's Es- 

 says towards a History of Painting, 1836. 



On the authority of Vasari, c. 21 ; but it is probably incorrect. Consult 

 James's Flemish and Dutch Schools of Painting, or Haydon's Lectures, 1844, p. 

 265. Cennini, translated by Mrs. Merriefield, 1844 ; Tambroni's Preface, p. 49. 



