Gesso (; 'chalk', from the , from ), also known as "glue gesso" or "Italian gesso", The Painter's Handbook: A Complete Reference by Mark David Gottsegen. p. 321 is a white paint mixture used to coat rigid surfaces such as wooden panel painting 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.
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.
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 ultraviolet (UV) light.
For priming flexible canvas, an emulsion of gesso and linseed oil, also called "half-chalk ground", is used.
target="_blank" rel="nofollow"> The Painter's Handbook: A Complete Reference by Mark David Gottsegen, p. 64
Acrylic gesso is a mixture of white pigment and some kind of filler (chalk, silica, etc.) and acrylic resin dispersed in water. It produces a soft, flexible non-absorbent surface that is technically not gesso (although it is commonly called that by its manufacturers). The Painter's Handbook: A Complete Reference, by Mark David Gottsegen. p. 321
It can contain calcium carbonate (CaCO3) to increase the absorbency of the primer coat as well as titanium dioxide or "titanium white" as a whitening agent. It is sold premixed for both sizing and priming panels and flexible canvas for painting. Art supply manufacturers market canvases pre-primed with acrylic gesso. Acrylic gesso can be colored, either commercially by replacing the titanium white with another pigment, such as carbon black, or by the artist directly, with the addition of an acrylic paint. Acrylic gesso can be odorous, due to the presence of ammonia or formaldehyde, which are added in small amounts as preservatives. Acrylic gesso's non-absorbent acrylic polymer base makes it incompatible with media that require an absorbent substrate, such as egg tempera. The Painter's Handbook notes a problem with using oil paints over an acrylic gesso ground instead of a traditional oil ground, citing a mismatch in flexibility that over time could cause the oil paint to delaminate.
Gesso can also serve as a base on three-dimensional surfaces for the application of paint or gold leaf.
|
|