The technique of Gouache or “Guazzo”
The technique of guazzo or, in French, of gouache, which is increasingly catching on among "rediscovered" artistic techniques, employs a type of pigment that has the same nature as tempera, but is made slightly more solid by adding plaster or white lead together with a compound of gum arabic.
The final solution is a pigment with a slightly duller colour than normal tempera. Already known and used in Europe in the sixteenth century, it was mainly used to make preliminary sketches for large oil works.
The great Italian decorative painters made great use of it for the sketches of the large fresco in the Renaissance palaces. In the eighteenth century it spread to France and in the nineteenth century it was widely used for the creation of advertising signs.
Dilutable in water, unscented and quick-drying, due to its composition it has a high reversibility feature, and therefore allows retouching the colours even if already spread and dried and permits to obtain shades equal to those of oil paint, in an opaque variant. The result is very opaque and satin.
A gouache work, at first sight, can very well be confused with an oil painting. Its brightness, given by its typical pearly colour, derives precisely from the addition of white lead or plaster.
This technique is still happily used in the production of decals, papier paint and in the current scenographic environments.
In foreign countries, the term gouache is often used instead of tempera, while the presence of gum arabic in the composition (also present as a binder in watercolour) makes this type of paint more elastic and dilutable in water without losing chromatic intensity; if we necessarily wanted to give a definition, it could be defined as a covering and concentrated watercolour.
This is the best for long projects because it can be rehydrated and used several times.
The problems that this technique have always brought with it are three:
- The pigment that is spread on the painting surface has a colour that changes during the drying process, the plaster tends to lighten the shade by almost 2 tones, so when you work in several stages this must be considered.
- The painter should pay attention to the thickness of the layer to be applied, because micro-cracks can appear, given by the amount of plaster inside the composition, which remains even after the drying process, reducing the uniformity and beauty of the painting.
- The painter should also pay attention to the painting surface, which must be very absorbent, such as paper, cardboard, terracotta or prepared with acrylic plaster, to ensure that the gouache does not come off.
What are the ideal brushes for this type of technique?
Ideal for the painting technique of the gouache are the series 105 and 107 Borciani and Bonazzi in sable, but not only, even the extra fine ox of the series 75 Borciani and Bonazzi is a guarantee, being a particularly opaque yield.
For those who prefer synthetic fiber, we recommend the line in synthetic fine gold of the 86 Borciani and Bonazzi series, versatile and cruelty free.
Thanks to its very soft and absorbent fibre, the Borciani and Bonazzi UNICO Mangusta 800 series, with anti-rolling, ergonomic and balanced handle, lends itself very well to the gouache, as well as the brush in soft white fibre of the 300 series, perfect for larger backgrounds.
Each brush is perfectly washable with water, and to keep even better over time and eliminate any pigment residues, it is advisable to use Borciani and Bonazzi vegetable soap in the practical aluminum box.
Gouache leaves no trace on the fibres, but it is ideal to use a set of brushes only for this technique.