A simple but serviceable compressor with 1.5 horsepower can be purchased reasonably cheaply at most DIY stores. These tend to be quite noisy machines. Much better for a shared workshop is a compressor with integrated air reservoir. These machines run very quietly.
A designer's airbrush compressor (shown left) which is entirely silent, uses a different technology. A basic airbrush nozzle (also shown) is reliable, cheap and easier to clean than more velaborate models. Designer's compressors and nozzles can be purchased from most large art material suppliers.
Universal Aquatint Solution
Simply add some Koh-i-Noor 3080-4 ink to Z*Acryl hard ground emulsion to obtain a black aquatint spray ink. The solution is liquid enough to be sprayed without further dilution, does not tend to clog the airbrush nozzle, and yields good results with all metal salt etching methods. The black dots are clearly visible, making spraying more reliable. Most other acrylics that are typically used for aquatint applications require dilution prior to use.
The following are examples of aquatint solutions you might use:
Example 1: Lascaux Aquatint Spray Resist (shown left)
Example 2: Mix Speedball with 20% to 30% water - this yields the most velvety tones; works best on copper.
Example 3: Mix some India Ink (ideally Koh-i-Noor) into an acrylic aquatint solution - use enough ink to get a black; test on paper.
Example 4: Mix one of the following binders--Lascaux 2060 OR Golden GAC 100-- with Koh-i-Noor, then with 20% to 30% water; excellent corrosion resistance and easy to strip.
Example 5: Use ready-mixed Badger Aquatint Solution for the best corrosion resistance on any metal and a traditional "dotty" look; available from Polymetaal.
Emma Gregory recently tested a range of possible aquatint solutions and published the results in Printmaking Today (2011).
For a base aquatint, aim for a density of dots that will cover between 40% to 50% (not more than 50%) of the plate surface. (Aim for a FINE MIST OF DOTS not a total covering).
Create marks on top of the aquatinted plate with Crisco, oil crayon, Scotch tape or acrylics; during etching these marks will remain lighter in tone. You may create successive layers of tone all the way from white via various layers of grey to black according to how long you etch the plate. You can create a whole tonal range in one etching stage simply by varying the density of the sprayed dots. You can also make blends, graffiti marks and stencil effects this way.
Or try dissolving some of the sprayed plate surface with water; you will get amazing random wash effects. After etching, any fatty deposits (Crisco or oil crayon) need to be washed off with soapy water. Acrylics can be stripped using soda ash or a citrus-based solvent (see below), or left on the plate for printing.
Tip: If you don't have a spray booth like the one shown here, improvise by filling a spray mist bottle with thinned Z*Acryl hard ground and simply spritz the plate. The effect will be more speckled, but it works!
|Protection against low level VOC exposure|
Today there are many paint products that are marketed as ‘safe’, yet there may still be harmful low-level VOC emissions, such as glycol ether. Examples: many water-based paints, acrylic floor finish, some artist acrylics, low odor, low VOC solvents, and printmaking resists.
Although a full organic respirator may be impractical for a day’s work we would recommend wearing a disposable light weight mask that offers some organic vapor protection. Dispose of the mask after a day’s work (about $ 5 per mask).
3M™ Particulate Respirator 8514, N95, with Nuisance Level Organic Vapor Relief
Safe Stripping with Orange Zest Solvents
An acrylic aquatint can be stripped off in a strong soda ash solution (1 part crystals to 3 parts warm water), or use one of the excellent citrus-based safe solvents now on the market (such as D*Solve by Z*Acryl) which remove acrylics with great ease.
"This truly revolutionary solvent was formulated as an alternative to petroleum-based turpentines and thinners. It is made from 100% renewable agricultural resources of soy, corn, and citrus, and is non-polluting, non-carcinogenic, and bio-degradable. Less than a teaspoon will thoroughly clean a large plate. DSolve will even strip dried ink from etched lines." Dick Blick
Image: Z*Acryl Product D*Solve
Etching an Aquatint
Typical etching times are as follows: -
Zinc etched in Saline Sulfate Etch
lightest grey......................1 secondgrey................................... another 5 seconds
darker grey....................... another 20 secondsand so on up to black..... about 10 to 15 minutesCopper etched in Edinburgh Etch
lightest grey..................... 5 secondsgrey.................................. another 20 seconds
darker grey...................... another 60 secondseven darker gray............. another 5 minutesand so on up to black..... about 30 to 45 minutes