A system used to apply liquid products by means of a fine spray. The liquid to be sprayed is usually contained in a metal can and is mixed with a gas that acts as a propellant. The jet is directed by a valve which, when pressed, releases a stream of liquid.
Insofar as printmaking is concerned, aerosols can be used to apply grounds since aerosol varnish resists mordants very well. Aerosols may also be used on stencil plates or to quickly cover the backs of plates to be bitten since such a ground dries extremely fast. Aerosols are also used when a product must be distributed quickly in a fine layer and in a superficial way as is the case with retarder thinners which are sprayed onto ink to prevent it from drying out between one work period and another. Aerosols are also used to spray silkscreens in order to remove the filler. Aerosols must be used with a certain amount of care. One must be careful to mix the product evenly with the propellant gas even though it is sometimes necessary to do the exact opposite by letting the can rest before use. The let (which should first be tried out on a piece of scrap paper) must be held 20 to 50 centimeters (8 to 10 in) from the surface to be treated and moved rapidly so that no puddles can form. It is best that the spraying be done in several layers (one thin layer at a time) rather than in one go. The finger placed on the release valve must not overlap or come into contact with the jet if spattering is to be avoided. [* etching ground]
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