Viscosity technique and 3D proof print

This topic covers a print test inked using the viscosity technique on a plate created with a 3D printer. The experiment was conducted by Marco Poma at the Il Bisonte Foundation, and both the finished work and the plate were made by Michele Bernardini, a student of the specialization course.

VISCOSITY TECHNIQUE

- Plate engraved at different depths

- Inking rollers of varying hardness

- Oil-based inks in different colors

- Magnesium

- Linseed oil

Colors with different viscosities juxtapose without mixing.

The viscosity technique was patented in the first half of the 20th century at Atelier 17 by the artist Stanley William Hayter in collaboration with his colleagues.

It is based on the principle of viscosity, where two liquids with different molecular friction tend not to mix. This technique allows a single plate to be inked with multiple colors, using a separate roller for each chosen color, with each ink having a different viscosity.

Inking is done exclusively with rollers, and the technique essentially has two different applications:

• Monotype: A layer of color is rolled onto a plate while masking or cleaning the areas designated for the next color. This process is repeated for each desired color.

• Relief and intaglio: By using rollers of different hardness, it is possible to achieve varying depths on the plate for each roller used. For this technique, it is essential to use a plate engraved at different depths, allowing each color to have its own gripping area.
  

Regarding the second method, I would like to provide a more detailed explanation, as it can be complicated to understand without hands-on practice.

Typically, three rollers are used: one hard, one medium, and one soft. Each color is associated with a specific roller:

• The most viscous color corresponds to the softest roller.

• The most fluid color corresponds to the hardest roller.

• The medium viscosity color goes with the medium roller.

The inks used are usually intaglio or lithographic inks, as long as they are oil-based.

To increase viscosity, magnesium is added to the color, while to decrease viscosity, linseed oil is used.

There is no rule regarding the number of rollers or colors used; two are enough to achieve the effect. If desired, an additional color can be applied in the intaglio manner, that is, inked manually and cleaned with tarlatan and tissue paper; in this case, this color must be applied first.

The diameter of the roller is important; it must be wide enough to cover the shorter side of the plate in a single pass to avoid a second pass that would mix the colors both on the roller and on the Plate.

Always start with the hardest roller, as the deeper parts of the plate must remain clean and inked only by the softer rollers.

Low viscosity

Medium viscosity

High viscosity

EXPERIMENT

I find this print test interesting as it attempts to apply viscosity on a plate made with a 3D printer. In fact, this allows for absolute precision in calibrating the different depths of the plate, making it ideally suited for the viscosity technique.

Plate made with a 3D printer.

For the test, three colors were created, ranging from the darkest to the lightest in shades of blue/aquamarine.

Here is the order of application using rollers of different hardness:

1. Hard roller - Low viscosity color

2. Medium roller - Medium viscosity color

3. Soft roller - High viscosity color

1°

2°

3°

Being a first experiment, the result, although satisfactory, shows an almost complete absence of the third color.

During the third attempt to roll the ink onto the plate using the softest roller, the ink did not reach the base of the plate. This meant that when the plate was printed the third colour was not visible. The final print is successful, however only two different colors can be clearly distinguished.