À la suite je repasse toutes les techniques de la gravure non-toxique
- Cliquez sur un sujet pour voir comment:
- appliquer le vernis
- exposer le film photopolymère
- de mordez la plaque et retirez le vernis
En ce moment les textes suivants n'existent qu'en anglais
acrylic etching grounds
As hard ground we use an acrylic floor polish.
This hard ground is extremely strong, and the plate can be wiped and printed while the hard ground is still on. You can work in the hard ground in exactly the same way as in the conventional hard ground. But you also have the option of doing washings in the hard ground with a mild solution of ammonia and water. Even the finest cross-hatchings will never cause the hard ground to break up during the etching process. A thin, even coat of hard ground is essential, as it will otherwise break up during etching.
The acrylic-based etching ground system offers a unique possibility of combining soft
and hard grounds. The etching ground
consists of a water-based ink for block prints mixed with an acrylic binder.
The water-based ink, which we used for rolled-on soft and hard grounds, also comes in a black version. It is coarser and contains more pigment. This makes it perfect for washes.
Aquatint is sprayed onto the plate with an
airbrush. The aquatint can be sprayed on
evenly, and etched and stopped out by turns
like a traditional aquatint. The airbrush can
also be employed in the creative process: you
can draw and paint with it, or spray it on in
layers of varying thickness. The main rule is
that the thicker the layer, the lighter the shade
of the final print in these areas.
The fact that oil repels water gives us many
sources for fat- or oilbased lift ground media.
You can use butter, lipstick, vaseline, wax
crayons, etc. In the Printmakers� Experimentarium,
however, we have developed our
own lift ground which serves for all types of
subjects: mix a tiny bit of etching ink with
olive oil to the desired consistency. You can
paint it on with a brush or write with it by
means of a pen directly on the de-greased
copper plate. It is important to use olive oil,
as this product enables the lift ground to
congeal if you put it in the refrigerator for a
few minutes. This prevents it from running
later in the working process.
Etching takes place in liquid ferric chloride. You can etch horizontally in photo trays or vertically in tanks. If you use a photo tray, mix a so-called Edinburgh Etch once and for
all: Dissolve citric acid powder in warm
water and add the 45 - 47 Beaumé degrees ferric chloride. The citric acid ensures a fast and accurate etching and also prevents the ferric chloride from crystalising during the process. This renders it unnecessary to sweep away crystals during the etching - you can
simply leave the plate with the art work facing upwards.This etching technique was developed by the printmaker Friedhard Kiekeben in Edinburgh.
Acrylic- and water-based etching grounds can be removed in a mild solution of soda crystals
and water. Soda crystals are best dissolved
in hot water. Soda is an alkaline product
which may irritate the skin. It is therefore
preferable to use rubber gloves while stripping
the etching grounds.
film photopolymères( sans morsure)
We use photopolymer film to transfer
drawings, photocopies, photographs and
computer generated stencils for intaglio prints. The thin film is sensitive to ultraviolet
light. Before use, the film must be
laminated onto the copper plate. The film is
sandwiched between two layers of protective
foil.
les 3 positifs
Le demi-teinte | Le ton continu | Le dessins au trait
The stencil must be transparent so you can
study it on a light table. Here we will transfer
a line drawing on overhead film, a
washing on drawing foil and a half tone
photograph on lith film. We will make all of
the three plates as non-etched intaglio plates.
The images will be transferred to the photopolymer
films on top of the plates.
Images transferred to photopolymer film can,
of course, be etched into the copper plate.
Before exposing the photopolymer film, you
need to thin it. Remove the top foil and save
it for later. Now put the plate in a fresh soda
developer under a lid for 20 to 30 minutes.
The developer thins the film evenly all over,
except for the edges: they will disappear. The
pre-developing time depends on the quality
of the water - that is, the amount of calcium
in the water. This means that a test has to be
made once and for all and the plate taken up
and checked at intervals. When small holes
begin to appear in the film it has been predeveloped
exactly 3 minutes too much.
At the Printmakers’ Experimentarium
the optimum pre-development takes 27
minutes at room temperature. When the plate
is ready, take it out of the developer and rinse
off the dissolved photopolymer film in cold,
running water. Dab it quickly in clean paper
and put it in the drying cabinet. The dabbing
must be swift to keep the paper from sticking
to the unprotected film.
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