Painting 1- Supports Grounds
Mål og innhald
Painting 1- Introduction to Supports, Sizes and grounds.
Students will be introduced to a variety of materials and methods
Krav til forkunnskapar
Students should have worked with painting before but this is an introductory course in relation to Supports, Sizes and
Undervisningsformer og omfang av organisert undervisning
Supports ¿ Materials and a short history
Supports can be rigid (fx. wood, metal, glass and stone), or flexible (fx. paper, card board and cloth)
Traditionally wood panels were used as supporting material for (smaller/transportable) paintings, like the Fayum
portraits (late Egyptian/early roman, on mummies) and icons (Byzantine and Medieval). In southern Europe poplar was
often used, in northern Europe oak is common for panels. During 1200 canvas is glued on top of the wood panels to
preserve the paintings better. Egg-tempera* is used for the panel paintings, laid in small brushstrokes since the paint
dries quickly. When one started adding oil (van Eyck, beginning of 15th C), it made the paint dry slower and gave
better painting qualities. Canvases becomes more common and oil paint more in use. During 1600 and Rembrandts
era, the use of drying oils as a medium for paint has completely taken over and big scale paintings is now possible
because of the use of cloth as a support. Canvases often consist of many pieces cloth sewn together. Fishbone
structure is often used, and under the thin layers of ground and paint with glazes, it enhances the vibration and livefullness
of the paintings.
During the 1950¿s-60¿s, the organic synthetic materials hit the art world, with plastics like acrylics, and cheap house
paint products come into use for largescale paintings.
When Jackson Pollock started to splash big amounts of paint on the canvas, cotton was used as it can suck up more
paint than linen. Cotton though is not as flexible fiber, and by time the heavy loads of paint has disfigured the big
canvas paintings with ¿bulges¿ and deformation caused by the paint.
Among the textiles, linen has the best properties (as well as hemp) and is mostly used, it¿s also better in an ecological
aspect (compared to especially cotton but also to synthetic fibers).
*(Tempera comes from ¿temperare¿ which means ¿ to mix¿ and actually just means a paint mixture, which can be
almost anything, but traditionally it stands for egg-tempera, or the fatter egg-oil-tempera).
Size ¿ What and Why
Size is a substance used to coat and fill the fibers of a support.
A size is a glue solution applied to the surface of the support to isolate it and thereby protect it against degrading
ingredients in the next coat, like linseed oil (that will otherwise rot, or ¿burn¿, the textile fibers by chemical reactions
and thereby make it fragile and eventually ¿cut¿ the fibers). The size will also make the canvas stiff (especially
linen/flax) as it will shrink into a well-stretched support to paint on. Often the same glue for the sizing (trad. hide glue
or gelatin) is the same as used in the ground. The size thereby also helps to bind the ground better to the support. The
traditional glues for the size and the ground, comes from animals, but also vegetable products, like starch (wheat, rice
etc.), can be used. There are also synthetic products. A fast and cheap material to use, for non-vegetarians, is gelatin.
It costs almost noting, is available in most food stores and just take a few minutes to prepare.
Applying size to a paper, makes it possible to paint on it with oil paints, without making the paint ¿bleed¿ (oil
penetrating the paper, discoloring it yellow and making it brittle) and thus separating binder (oil) from the pigment,
leaving the paint/pigment dry and hard at the surface, eventually peeling off.
The size shall fill the fibers enough to protect them, but not show/penetrate to the back, where it might be sticky in
high relative humidity, leading to adhering dust and possible mold growth.
Ground ¿ Why and What
Grounds are layers, or coats, applied to a support to paint on.
The ground works as a support for the paint, giving the painting a certain expression and color, contributing to a matt
or half matt/half fat expression of (oil-) paints. The ground, as well as the size, prevents the binder/paint to suck into
the support and gives a background to paint. It can be more or less smooth, showing more or less of the canvas
structure. There are different weaves made up of different types of fibers. The threads in the weft can be of different
thickness, and the cloth more or less tight/loosely weft. The gaps between the threads are filled with the ground, so
that paint stay on the surface and doesn¿t penetrate onto the canvas¿ back.
The most common are white grounds today, but it could be any color, depending on the pigments in it. A white ground offers the brightest reflecting surface for the light to act upon. Traditionally this has been a gesso or a white lead oil
ground. In 15-18th C, dark grounds in red/brown and grey/black were used (made with stable mineral earth pigments,
both cheap and easy to get), giving a background to glazes end several thin paint layers put on top, giving a very
vibrant 3D image and a fantastic ¿chiaro-scuro¿ (light-dark) sensation (fx. Tizian and Rembrandt). The traditional chalkglue-
ground, consists of chalk (works as a filler/gives body, dries quick and contributes to a matte ground), hide glue
(also called rabbit skin glue, but doesn¿t necessarily arrive from rabbits..) and zinc white mixed with titanium white (to
make it closer looking to the traditional lead white, now forbidden because it¿s toxicity).
The ground makes the canvas more rigid to work on, but by time, when all the materials in the painting ages (gets
yellowed, darkens, gets brittle, gets hard etc.), and less flexible, it can¿t take the moving (shrinking ¿ swelling) caused
by fluctuating relative humidity, as good. That leads to the craquelure of the painting (cracks in ground and paint
layers), risking paint to fall off.
The best way to prevent this, is to keep paintings (on hygroscopic* materials like canvas and paper) away from outer
walls, direct sunlight, radiators/heating sources and so on).
*(A hygroscopic material takes up and gives away moist from the air)