Pigments and Equipment for
Fresco Painting

Therefore, the list of pigments available to the fresco painter is comparatively limited, containing only those colors that remain unaffected both by acids in the air and the alkaline action of lime. [p. 6]

Pigments for fresco painting should be resistant to the strong alkali action of lime and must also set well in the plaster lest they powder off like pastel.

The following pigments can be used:

Black

Ivory Black
Mars Black

Yellow

Cadmium yellow, deep--sometimes suggested but it should be checked for fading
Mars yellow
Raw sienna
Yellow ocher

Red

Cadmium red--recommended by some artists, questioned by others. I have seen examples used in indoor frescoes that have remained in good condition over twenty years.

Earth reds [English, Indian, Light red, Venetian] Mars red
Pozzuoli red--when genuine it is like a cement. Other colors may not set well over it. Therefore it should be used only in top layers of a fresco painting.

Blue

Cerulean blue
Cobalt blue
Ultramarine blue--If of good quality it should not react to lime but may bleach out because of the action of polluted air containing dilute acids. It is not recommended for fresco, although it has survived in interiors in clean country air unpolluted by corrosive city smoke.

Green

Chrome oxide opaque
Cobalt green
Terre vert
Viridian

Violet

Cobalt violet--should be tested before use for its setting action in lime. The poisonous cobalt violet [cobalt arsenate] should be avoided.
Mars violet
Ultramarine red and violet--under some limitations as ultramarine blue.

Brown

Burnt sienna
Burnt umber--sometimes sets badly and powders off wall.
Raw umber

White

Lime putty
Titanium dioxide
Bianco sangiovanni--the preparation of this white is described by Cennini. It is still considered the most appropriate white for fresco technique by many painters -
A note on the making of bianco sangiovanni:

1. Little cakes of well-aged lime putty are put out in the air to dry solid.

2. When thoroughly hardened, they are crushed, ground to a smooth paste with a little water, and made again into cakes which are set out to dry again. The whole process is repeated two or three times. At this point the lime should have thoroughly combined with carbon dioxide, like a dry mortar wall, and should have no more binding power.

3. The cakes should be ground with water to a creamy consistency by means of a muller and grinding slab. The mixture should be strained several times through a brass screen and will then be ready to use. [p. 183]

On a glass slab all colors are ground with distilled water to paste consistency, using a muller or a spatula. Then, like pastes for egg tempera painting, they can be stored in clean screw-top jars. A little water should be gently poured over the top of the paste to keep it from drying out. The jar covers should be made of plastic, rather than metal, so that they will not rust.