4
Experiments and Creation of Frescoes. To be completed over a two-week period. .
Part A. Making a Tile Fresco.
(Week 1) Preparation of the Arriccio. Preparation of a wall for painting involves several
layers of mortar, including an initial very rough layer of cement. By using a tile as the
foundation, we will use only a single layer of lime plaster for the arriccio and forego the
cement.
1. Mix the arriccio as two parts sand and one part slaked lime. (For two 2" x 2" tiles,
measure out 50 ml of sand in a plastic beaker and then use 25 ml of slaked lime. Mix in
250-ml plastic beaker.) Mix well. You may need to add water if the lime sample was not
wet; on the other hand, the plaster will crack if it is too wet.
2. Obtain a tile which has been soaked in water overnight. Dry it until the surface is no
longer shiny.
3. Apply the plaster evenly over the rough side of the tile to a thickness of about 3 mm,
thinner that for an arriccio on a wall. Save a small amount of the arriccio plaster for
testing; label the beaker in which it was mixed and store until Week 2.
4, Let the plaster dry for 10 minutes; the tile will absorb the water.
5. Smooth the surface of the plaster with a spatula to give a relatively uniform surface.
6. Let the tile dry for a minimum of two days so that the plaster is converted to calcium
carbonate (carbonation).
Between Day1 and Day 2. Preparation of the senopia.
Sketch your picture on tracing paper (provided). Use a tracing a pin to perforate the
paper along the lines of your sketch. Plan the color scheme for your fresco and list
pigments appropriate for it. (Large fresco wall paintings begin with a rough sketch on the
arriccio. This sketch is then transferred to paper.)
(Day 2) Preparation of the intonaco and giornata.
1. Mix the intonaco as one part slaked lime and one part finely powdered sand. (For a
two 2" x 2" tile, measure out 50 ml each of sand and 25 of slaked lime. Mix in 250-ml
plastic beaker.)
2. Thoroughly wet the arriccio and the tile. Then spread the plaster evenly to a thickness
of about 2 mm. Let the tile dry about ten minutes.
3. "Polishing" the intonaco orients the sand and gives a smooth, polished surface.
Smooth the surface in a single direction with a large, clean spatula. Remove any large
granules that pop up and replace any miss plaster.
4. Apply a small brush stroke of water to ascertain if the surface is ready for painting. If
the plaster readily absorbed the water, it is dry enough for painting.
5. Transfer the outline of your picture onto the plaster surface by laying the sinopia on
the tile and pouncing with a lime-compatible pigment. Instead of pouncing, you may
wish to gently incise the drawing into the plaster through the tracing paper.
6. Select the pigments and prepare them for painting by grinding a small amount in
distilled with a flat spatula on a glass plate. The pigment preparation is ready when a
small amount, dropped into water, mostly floats and does not sink. The pigment is
applied as a dilute wash.
7. If you have prepared more than one tile, number each and record the name and
formula of pigments used for each in your notebook. Paint a strip of the pigment for color
reference as well.