300 Improvements in the Aquatinta Process. 
it not come off very freely, put your walling-wax round the 
margin of your plate, and then pour on the touches some 
warm water, but care must be taken it is not too hot. 
The touches now being clean taken off, wash the plate 
well and clean from all impurities and sediment of the ink, 
with cold sofé water, then dry the plate at a distance from 
the fire, or else in the sun, and when dry, pour on your 
aquafortis, which should be in cold weather as follows : 
To one pint of nitrous acid, or strong aquafortis, add 
two parts, or twice its quantity of soft water. 
In hot weather, to one part of nitrous acid add three parts 
of water. 
In every part of this process avoid hard or pump water. 
The last process of biting in with aquafortis must be 
closely attended to, brushing off all the bubbles that arise 
from the action of the aquafortis on the copper. 
In summer time it will take about twenty minutes to 
get a sufficient colour: in winter perhaps half an hour, or 
more. All this must depend on the state of the atmosphere 
and temperature of your room. If any parts require to be 
stopt out, do the same with turpentine-varnish and lamp- 
black, and with a camel-hair brush pass over those parts 
you consider of sufficient depth; distances and objects re- 
ceding from the sight of course ought not to be so deep as 
your fore-grounds; accordingly you will obliterate them 
with the foregoing varnish, and then let it dry, when you 
will apply the aquafortis a second time, and repeat this just 
as often as you wish to procure different degrees of colour. 
Every time you take off the aquafortis the plate must be 
washed twice with soft water, and then set to dry as before. 
To ascertain the depth of your work, you should rub a 
small part with a piece of rag dipped in turpentine, and 
then apply the finger, or a piece of rag rubbed on the oil- 
rubber, to the place so cleared, and it will give you some 
idea of the depth. 
The walling-wax is taken off by applying a piece of 
lighted paper to the back of the plate, all round the opposite 
parts of the margin where the wax is placed; then let the 
plate cool, and the whole of the grounds, &c. will easily 
come off by washing the plate with oil of turpentine, which 
must be used by passing a rag backwards and forwards, 
until the whole dissolves: it is then to be cleaned off by 
rags; and care must be taken that no part of the turpentine 
is left hanging about the plate. 
The plate should only pass once through the press. 
Directions 
