436 ENGRAVING IN AQUA TINTA. 



over with a weak and thin varnish of turpentine, 

 asphaltum, or mastich, and then suffered to dry, 

 when the aqua fortis is poured on. The varnish 

 will immediately break up in the parts where the 

 treacle mixture was laid, and expose all those places 

 to the action of the acid, while the rest of the plate 

 remains secure. The effect of this will be, that all 

 the touches or places where the treacle was used 

 will be bit in deeper than the rest, and will have all 

 the precision and firmness of touches in Indian-ink. 



After the plate is completely bit in, the border- 

 ing-wax is taken off, by heating the plate a little 

 with a lighted piece of paper ; and it is then cleared 

 from the ground and varnish by oil of turpentine, 

 and wiped clean with a rag and a little fine w^hiting, 

 when it is ready for the printer. 



The principal disadvantages of this method of 

 aqua-tinting are, that it is extremely difficult to 

 produce the required degree of coarseness or fine- 

 ness in the grain, and that plates so engraved do 

 not print many impressions before they are worn 

 out. It is therefore now very seldom used, though 

 it is occasionally of service. 



We next proceed to describe the second method of 

 producing the aqua-tint ground, which is generally 

 practised. Some resinous substance is dissolved 

 in spirits of wine, as common resin, Burgundy- 

 pitch, or mastich, and this solution is poured all 

 over the plate, wdiich is then held in a slanting 

 direction, till the superfluous fluid drains ofl'j and 

 it is then laid down to dry, which it does in a few 

 minutes. If the plate be then examined with the 

 magnifier, it \\i\\ be found that the spirit, in evapor- 

 ating, has left the resin in a granulated state, or 

 rather, that the latter has cracked in every direc- 

 tion, still adhering firmly to the copper. 



