Etching and aquatint (Zea Mays Acrylic Aquatint and Stop Out)
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.
Using an Airbrush
For smooth coatings and best results airbrushing is typically done in a zigzag pattern. The atomized spray droplets are evenly applied to a clean surface in regular passes. Multiple passes are overlaid at 90 degree angles to achieve the desired thickness.
Airbrush compressors come in two types: silent compressors for hobby and artist use, and much more powerful piston compressors for industrial and automotive applications (the noisy kind). Both types work best when fitted with an air reservoir tank, as this allows for a steady supply of air pressure.
Can acrylics be hazardous? The answer is : Y E S read more here:
|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
shown: (left) Mark Zaffron’s pioneering acrylic hard ground from the 1990s,
most kinds of acrylic floor varnish may serve as a substitute;
(right) the addition of black ink helps make the dots much more visible on
reflective metal surfaces
Creating an Acrylic Spray Aquatint
Researchers: Audrey Blood and Jenny Gover
Aquatint is a method of creating tonal value in intaglio printmaking. An acrylic ground is applied in a fine particulate spray onto a degreased plate and then hardened. The acrylic spray acts as a resist, allowing acid to bite around the particles of ground that have adhered to the surface of the plate, creating a smooth, even tone.
Our task was to create a formula to replace our existing acrylic spray aquatint mixture, which was no longer in production. We began by researching several different formulas and assessing them for quality and durability. We based our mixtures on recipes from the Edinburgh Printmakers (www.edinburghprintmakers.co.uk), Friedhard Kiekeben of www.nontoxicprint.com, and the experiments of Tracy Hill and Emma Gregory (nontoxicintaglio.tumblr.com) Links to all of our tests appear below.
Universal Aquatint Solution
Simply add some Koh-i-Noor 3080-4 ink to Z*Acryl hard ground emulsion (unavailable) to obtain a black aquatint spray ink. Today, you may substitute this product with one of the many updated acrylic floor finish products listed on the page :
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 or other safer 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!
An acrylic hard ground 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', 'CitraSolv', or 'De-Solv-it') which remove acrylics, etching grounds and hardened ink and paint with great ease. Note: some cheap prodcuts are mixed with mineral spirits, and do not offer improved safety.
'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.'
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
Throughout the 20th century artists used alternative methods for
obtaining aquatint-like tonal qualities without the expense of
larger equipment such as a rosin box, or more recently,
an airbrush compressor.
The most commonly mentioned method
involves using sandpaper that is imprinted in an etching
ground in successive passes on an etching press,
resulting in pitted areas and
printing as tonal areas, once etched.
From the 1980s artists sometimes used cans of
spray paint as an improvised aquating medium,
and the results are on a par with rosin
aquatint, as well as very acid resistant.
(use respirator and ventilation).
Cedric Green developed a different approach
which is outlined below:
AND SUGAR LIFT
by Cedric Green
note: the salt tint, and sugar lift tint approaches outlined
here are a professional form of aquatint that is
usable in any form of intaglio etching,
not just in electro-etching
tinting methods with ink ground
The most commonly used traditional method for applying an even grain over a etching plate intented to print an even tone, is rosin aquatint. But there are many people who are allergic to the very fine rosin dust and who cannot afford the expense of a high quality sealed aquatint box.
In addition the process of melting the grains of rosin on the plate will produce fumes that are very dangerous and carcinogenic. Another method of producing an aquatint texture is with asphaltum powder which has to be melted and which also produces carcinogenic fumes.
I have developed 3 alternatives to rosin or asphaltum aquatint, the first of which which I call 'fractint' because of the textures produced sometimes can resemble some computer generated fractal patterns. It relates closely to ink ground in that it uses linseed oil-based relief printing ink which functions as an resistant layer which is not soluble in water.
The other two methods must also be used with an ink ground, and are salt aquatint, and sugarlift tinting.
After applying a thin even coat of stiff ink to the plate with a soft roller (treothene or similar), and before it is dry, it is placed face-down against a flat smooth non-absorbent surface like a polished metal plate or a rigid smooth plastic sheet, and then put through an etching press taking care not to let it slip against the surface.
This can be done by laying strips of card slightly thicker than the plate on either side, projecting towards the roller to lift it to the level of the plate edge. Then the plate is pulled carefully off the surface, and the ink will be found to have formed a fine complex branching organic pattern which fills the spaces between any previous lines or lowered areas.
"Casse noix" - etching and fractint using ink ground -
zinc plate printed in intaglio and relief - 25 cms square
The ink in fact is 'pulled' into tiny ridges and valleys by suction between the surfaces, and the scale of the pattern is dependent on the viscosity of the ink and on the fine structure of the smooth surfaces. A slightly matte surface generally gives a finer pattern. A thick viscous ink, but rolled down on the inking slab to a thin layer gives the best results.
Black ink gives finer results in general, but white ink leaves the underlying design easier to see.
When the ink has dried, it can be treated like an aquatint, progressively stopped with ethanol/shellac varnish, and etched in stages. Fractint is generally more suitable on a plate with etched lines than on a plain plate, although it can be used as a pure tone method. Fractint is very sensitive to specks of dirt, hairs, and bits of skin in the ink and produces patterns around any 'impurities' on the plate or plastic sheet.
Often these are interesting and can be incorporated, but to avoid them, the ink must be very smooth, without lumps, and the plate, plastic sheet, inking slab, and rollers should be wiped clean before starting.
Magnified fractint texture - from proof pulled from a copper plate.
Note vertical line to the right which was a slight scratch on the plate,
showing how sensitive fractint is to fine lines on the platesalt aquatint
The second method using ink ground, is an adaptation of salt tint, which has been used before with traditional grounds, but which, when used with an ink ground, has the advantage over fractint of very closely resembling resin aquatint The grain produced can be much finer than with fractint.
But this use of it also has the advantage of not requiring an expensive aquatint box or needing to be heated to melt it onto the plate (the fumes from heated resin are as damaging as turpentine fumes).
Equipment needed for salt tint – ink grounded plate
on card, sieve, pestle and mortar, salt
First the plate is grounded with ink as for needling or as for fractint, but without cobalt dryers. The ink ground should be as even and thin as possible. Then the plate is laid face up onto a sheet of paper or card larger than the plate. While the ink is still wet, a layer of fine salt is sieved all over the plate, until it is even all over. It does not matter if it ends up quite thick.
The salt may need to be ground in a pestle and mortar if comes out of the packet too coarse. You may have to make a special sieve (as illustrated) with a finer mesh than the average domestic sieve.
magnified photograph of copper plate with reticulated black ink
ground after salt tint has been dissolved
Lift the plate and card carefully and transfer it onto the bed of the etching press. Lay another sheet of thick paper over it all. Back the sandwich with a thick felt blanket, and roll it through the press. The salt lying on the ink ground will be pressed through to the bare plate, displacing the ink and forming a finely reticulated pattern which closely resembles a resin aquatint.
How fine the texture is depends on how finely the salt is ground and the mesh of the sieve used to apply the salt to the inked plate.
After the ink has completely dried, perhaps accelerated by putting it in the sun, or on a hot plate, shake off the excess salt, and lay it in a tray of warm water to dissolve the salt.
The plate can then be stopped out exactly as if it is a resin aquatint, and galv-etched or if it is a zinc, aluminium or steel plate, etched in Bordeaux etch.
Small print from needled, salt tinted and galv-etched copper plate
sugar lift tint
Traditionally, sugar lift has to be given a grain by aquatinting it so that it prints dark in intaglio. But the combination of ink ground with sugar lift can be used to advantage to produce a texture without the separate step of aquatint, and will provide a 'tooth' to hold the ink within the sugar lift area, in a one step process.
Sugar lift is used because it is a positive process - that is, if the plate is to be proofed in itaglio, what you see is what you get. But with an ink ground rolled over the dried sugar, the ink is forced through the cracks in the sugar to form small lines and dots which reveal the brushstrokes and different thicknesses of the sugar..
Small copper test plate after sugar lift tinting and stopping
in 7 vertical steps of about 15 minutes at 1 volt.
The way that this is done is as follows:
1 Prepare a saturated solution of sugar dissolved in distilled or demineralised water, add a few drops of black Indian Ink to colour it, and a drop of washing up liquid or liquid soap to help it to stick to the plate.
2 Apply the sugar lift solution thinly to a well degreased plate with a brush, as evenly as possible, to those areas to print as a tone.
3 Allow it to dry a little, hastening it if required with a hair dryer, until it is tacky.
4 Then carefully blot the whole plate or the areas you want to print with a tone with a sheet of tissue paper. Smooth the tissue paper down gently over the areas of sugar lift until you can see the sugar lift through the tissue paper. Areas of sugar lift that have been applied very thinly showing the brush strokes can be allowed to dry and do not need blotting.
- intaglio proof of test plate above (left)
- Proof of print showing fine texture from sugar lift tint on a zinc plate. This texture is produced by varied brush strokes and the thicker sugar strokes blotted several times. It was etched in 5 steps of 5 minutes each at 2 volts (center)
- Zinc plate for "Greenland" prepared with sugar lift. Note little polished zinc 'palette' to test and thin the sugar lift on the brush. Plate size 250 x 330 mm. (right)
With practice you can judge how to vary the final effect by varying how hard you press the tissue against the sugar lift, or the number of times you repeat the blotting process. Peel off the tissue paper each time and discard it. The tacky sugar lift areas should be matte instead of glossy.
Let the sugar lift dry further, If is has dried too much and does not feel slightly tacky, breathe on it to make the suger absorb the moisture of your breath, until it feels tacky again.
Then apply the ink ground with a soft roller (treothene or similar), pressing the ink hard into the sugar lift, to squeeze it through the pores created in the film of sugar, and to press the ink in around the edges of the areas of sugar solution.
The ink should be mixed with a few drops of siccative or cobalt driers, and should not be too oily.
The oily ink will draw away from the slightly damp sugar lift areas as it dries and the texture created should be visible as a fine network of lines of ink. How fine the texture is depends on how tacky the sugar was when the ink was rolled over it.
The drier is is, the finer the texture. After the ink has completely dried, perhaps accelerated by putting it in the sun, or on a hot plate, or under a tungsten lamp, lay the plate face up in a tray of warm water and the sugar will dissolve. It will all dissolve without touching the surface. Do not brush it, and after 5 to 10 minutes lift the plate very gently out of the water keeping it horizontal.
Let it dry without blotting it or wiping it, and it will be ready to etch. A variety of textures and of degrees of granularity can be produced with experience. The secret is not to remove too much of the sugar lift by being too impatient and blotting it too soon. The ink should be allowed to dry properly before putting it in water and etching it.
Sugar lift tint has become my method of preference for its qualities of reproducing brushstrokes, producing fine grain with character, and the speed with which it can be done with fewer processes and controllable accidents....