440 ENGRAVING IN AQUA TINTA. 



two, three, four minutes, or longer. Observations 

 of this kind, frequently repeated, and with diifer- 

 ent degrees of strength of the acid, will at length 

 assist the judgment, in guessing at the tint which 

 is produced in the plate. A magnifier is also use- 

 ful to examine the grain, and to observe the depth 

 to which it is bit. It must be observed, that no 

 proof of the plate can be obtained till the whole 

 process is finished. If any part appears to have 

 been bit too dark, it must be burnished down with 

 a steel burnisher ; but this requires great delicacy 

 and good management not to make the shade 

 streaky ; and as the beauty and durability of the 

 grain is always somew^hat injured by it, it should 

 be avoided as much as possible. 



Those parts which are not dark enough must 

 have a fresh grain laid over them, and be stopped 

 round with varnish, and subjected again to the 

 aqua fortis. This is called re-biting, and requires 

 peculiar care and attention. The plate must be 

 very well cleaned out with turpentine before the 

 grain is laid on, which should be pretty coarse, 

 otherwise it will not lay upon the heights only, as 

 is necessary, in order to produce the same grain. 

 If the new grain is different from the former, it 

 will not be so clear nor so firm, but rotten. 



We have now given a general account of the 

 process of engraving in aqua tint, and we believe 

 that no material circumstance has been omitted, 

 that can be communicated without seeing the 

 operation ; but after all it must be confessed, that 

 no printed directions whatever can enable a person 

 to practise it perfectly. Its success depends upon 

 so many niceties, and attention tp circumstances 

 apparently trifling, that the person who attempts 

 it must not be surprised if he does not succeed at 



