29f) On the Preparation and Use of Copal Varnish. 



drying, thin them with pure turpentine. I purposely make the 

 varnish so thin as not to shine when tlie paint is dry ; but if it 

 work too dry, moisten with a little more varnish till right ; and 

 if it become too thick so as to work gumniv, add powder co- 

 lour aiu! turpentine till it is brought to a proper consistence. 

 I keep these saucers of colour clean in a small chest of drawers, 

 by which I have a great many in a little compass ; and the co- 

 lours are continually set for use, as they oiilv require moistening- 

 in the morning with turpentine. I do not however always wait 

 to soften them in this way, but put fresh colour upon tlie old, out 

 of the bottles. 



The colours work freest, and dry quickest, when they do not 

 shine, and will remain exactly as you put them on ; but if there 

 is too much varnish, and the canvass is painted frequently over 

 in the same day,the sharp touchcsvvill spread a little; a fault which 

 must be avoided bv using no more varnish than just enough to 

 shine, and by drying the part more perfectly l)efore painting on it. 

 In cold weather, the drying may be effected by the fire, or by hold- 

 ing a hot iron before the canvass; in cold weather, vou must not ex- 

 pose the painting to a hot fire directly afterwards, as it would 

 melt and run, but let it dry two or three hours, and then bring 

 it to the fire to finish. The picture may be varnished with the 

 same varnish made thicker (if you wish to be sure of the purity 

 of the materials), and when varnished, dry it as soon as convenient 

 by gradually approaching the fire, avoiding a heat that would 

 melt the copal. After this perfect drying, no dirt or smoke will 

 ever stick to the picture ; but it may be dusted or washed quite 

 clean with pure water, and will never change. 



The next varnish I generally employ is made in the following 

 manner : Take the sediment of the first varnish or fresh copal 

 beat small ; cover it to about twice its height with turpentine in 

 which camphor is dissolved, (an ounce to a quart,) cork it up, 

 shake it well, and put it by for a year, at the end of which it will 

 be dissolved. The first portion that is dissolved thickens the tur- 

 jjentine, and enables it to dissolve the remainder ; but if the tur- 

 pentine is too much diluted, the remainder will never dissolve, so 

 tiiat it is easier to make thick camphor varnish than thin. It 

 must not, however, be made too thick at first; but when that 

 which is put by is thick enough, pour it off for use, and add fresh 

 camphor and turpentine to the remainder, and put it by again till 

 dissolved, which it will be in the course of time. If you want that 

 which is put by before it is quite dissolved, it may then be put in 

 a saucepan of cold water with the cork loosened, and made to 

 boil for an hour, stirring it well up two or three times towards 

 the end, and that will finish the dissolution. 



1 paint small pictures on the finest mill-boards glued to a deal 



frame. 



