Gesso

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A restored gesso panel representing St. Martin of Tours. From St. Michael and All Angels Church, Lyndhurst, Hampshire

Gesso (Italian pronunciation:

Latin: gypsum, from Greek: γύψος), also known as "glue gesso" or "Italian gesso",[1] is a white paint mixture used to coat rigid surfaces such as wooden painting panels or masonite as a permanent absorbent primer substrate for painting. It consists of a binder mixed with chalk, gypsum, pigment, or any combination of these.[2]

Gesso is used in painting as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it.

Characteristics

The colour of gesso is usually white or off-white. Its absorbency makes it work with all painting media, including water-based media, different types of tempera and oil paint.

Mixing and applying it is a craft in itself, as it is usually applied in ten or more extremely thin layers. The hide glue mixture used to make the traditional gesso is rather brittle and susceptible to cracking, thus making it suitable for rigid surfaces only.

When painting, there are several advantages to using gesso. It provides a strong foundation for the paint to adhere to, prevents the paint from soaking into the surface, and can also be used to achieve a desired texture or surface finish. Furthermore, Gesso can help to extend the life of a painting by acting as a barrier to protect it from moisture, dust, and UV rays.[3]

Composition

Acrylic gesso

Gesso is traditionally a mix of an animal glue binder (usually rabbit-skin glue), chalk, and white pigment.

For priming flexible canvas, an emulsion of gesso and linseed oil, also called "half-chalk ground", is used.[4]

Acrylic gesso is a mixture of white pigment and some kind of filler (chalk, silica, etc.) and

oil ground, citing a mismatch in flexibility that over time could cause the oil paint to delaminate.[8]

Uses

Gesso is used by sculptors to prepare the shape of a final sculpture (fused bronze) or directly as a material for sculpting. Gesso can also be used as a layer between sculpted wood and gold leaf.[9] In this case, a layer of refined and coloured clay called 'bole' is used to cover the gesso before applying the gold.[10] Bole is usually red in colour.

It is also used as a base on three-dimensional surfaces for the application of paint or gold leaf.[11]

References

External links

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