44 



Processes and Schools of Engraving. 



G. AQUATINT. 



Process. 



Tone-effects, of a more transparent quality but of less depth and 

 richness than mezzotint, are obtained by the method of aquatint. It 

 gives the nearest imitation that prints can offer of the quality of the 

 washes of water-colour. As the name implies, the tone or tint is obtained 

 by biting with the acid (aqua fortis). The essential element of the 

 process is the partial protection of the surface of the plate with a porous 

 ground, through whose pores or reticulations the acid can bite. 



There are two methods of laying the ground forming (a) the dust 

 ground, (b) the spirit ground. 



In the first method (a) powdered asphaltum or resin is placed in a 

 box and blown into a cloud by bellows, or by a fly-wheel worked from 

 without ; the plate is then put into the box to collect the dust which 

 descends in a regular coating on to its surface. This porous coating, or 

 ground, is then fixed to the sui'face by heating the back of the plate. 

 By the second method (b) resm is dissolved in sphits of wine, and the 

 solution spread evenly over the surface of the plate. As evaporation 

 takes place the resin will be left in a grain on the surface. 



The porous ground being laid, an even tint, varying according to the 

 grain or reticulation of the ground, could be obtained by biting with the 

 acid. But before bitmg, the etcher will cover those parts of the ground 

 where he wishes to obtain pure white with protecting varnish, and allow 

 the rest of the plate to be bitten to the depth of his next lightest tone. 

 He will then cover with varnish in the same way such parts of the plate 

 as he wishes to remain in this light tone, biting again, and varnishing 

 again in stages, until the parts which have been constantly bitten are, of 

 course, his darkest portions. 



A grained surface similar to aquatint can also be produced hy other 

 means. One of these {sand-grain) is obtained by sand-paper, pulled 

 through the press in conjunction with the copper plate, whose surface it 

 roughens. By another method {sulphur -tint) powdered sulphur is dusted 

 on to the surface of the plate which has been spread with a layer of oil. 

 The particles of sulphur gradually corrode the surface in a delicate grain. 

 Effects of wash can also be achieved by leaving acid in patches on the 

 surface of the plate. For the sake of convenience these analogous 

 methods, by which similar effects to aquatint are x^roduced, are classed 

 under the same heading. 



History. 



Jean Baptists Le Prince (Metz, Paris, Eussia ; 1734-84), v/hose 

 earliest dated aquatiats belong to the year 1768, is generally regarded as 

 the inventor of the process. Ploos van Amstel (Amsterdam ; 

 1726-98), in his Imitations of old master drawmgs, L. M. Bonnet (see 

 section on StixDple, p. 42), and P. G-. Floding (Stockholm, Paris ; 

 1731-91), were producing plates in a style bordering on aquatint some 

 years before this date ; but their usual methods show a considerable 



