On the Art of Aquathita Engraving, 131 



artist, who for a long time kept his process a secret. It 

 has, however, been much improved since. It consists in 

 corroding a copper-plate with aquafortis in SL-.ch a manner 

 that an impression from it has an appearance very much 

 resembling a drawing in Indian ink. " This is effected by 

 covering the copper with a powder or some strbstance which 

 lakes a granulated form, so as to prevent the aquafortis from 

 .acting'whcre the particles adhere, and bv this means cause 

 it to corrode the copper partially and in the interstices only. 

 When these particles are extremely minute, and near to 

 each other, the impression from the plate appears to the 

 naked eye exactly like a wash of Indian ink. But when 

 they are larger, the granulation is more distinct ; and as 

 this may be varied at pleasure, it is capable of being adapted 

 with great success to a variety of purposes and subjects. 



" This powder or granulation is called the aquatinta 

 grain, and there are two general modes of producing it. 



" We shall first describe what is called the powder grain, 

 because it was the first that was used. Having etched the 

 outline on a copper-plate prepared in the usual way by the 

 coppersmith, (for which see the article Etching,) some sub- 

 siance must be finely powdered and sifted which will melt 

 with heat, and when cold adhere to the plate, and resist 

 the action of aquafortis. The substances which have been 

 used for this purpose, either separately or rnixcd, are as- 

 phaltum. Burgundy pitch, resin, gum-copal, and gum- 

 mastic ; and, in a greater or less degree, all the resins and 

 gum-resins will answer the purpose. Conmion resin has 

 been most generally used, and answers tolerably well ; 

 though gum-copal makes a grain that resists the aquafortis 

 better. The substance intended to be used for the grain 

 must now be distributed over the plate as equally as possi- 

 ble ; and different methods of performing this essential part 

 of the operation have been used by different engravers, and 

 at different times. The most usual way is to tie up some 

 of the powder in a piece of muslin, and to strike it against 

 a piece of stick held at a considerable height above tiie plate. 

 By this, the powder that issues falls gently, and settles 

 equally over the plate. Every one must have observed how 

 uniformly hair-powder settles upon the furniture after the 

 operations of the hair-dresser: this may afford a hint to- 

 wards the best mode of performing this part of the process. 

 The powder must fall upon it from a considerable height, 

 find there must be a suflicicntly large cloud of dust formed. 

 Tlie plate, being covered equally over with the dust or pow- 

 der, the operator is next 10 proceed to fix it upon thu plate, 

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