Post 315 – by Gautam Shah
Tempera is style of painting, relying on pigment binding property of materials like gum, eggs, starch etc. The binder also help in fixing the pigments onto surfaces such as, fabrics, masonry plasters, canvas and wood. It is one of the oldest method of colour coating application and has been practised in various civilizations. It is as much an art painting process as it is an architectural surface coating system.
The word tempera derives from the verb temperare – to temper. It carries the meaning, to mix properly or regulate or change in a controlled manner. Tempera as a painting style either developed concurrently with STUCCO or followed it to ‘temper’ it. Stucco paintings were application (impregnation) of colour pigments into wet (green) plasters. It was not possible to create micro zones of varied colours or diffuse the colours across at the boundaries. This was corrected by tempering the painting with overdrawing the shading effects. When the shading effects were applied, the stucco plaster had hardened. Tempera, a coating consisting of binder, water and colour pigments was used as a paste.
Tempera was touching coating application. It was possible to apply it in very small sections, with very fine line strokes and in desired intensities to create the effect of miscibility or transparency. Tempera colours have a slight sheen compared to a dull-flat surface of stucco paint. In later periods, little additional gloss was achieved by applying neat binder (with water but without the colourants). For the same purpose, at places wax or ENCAUSTIC, oils etc. were also applied. Tempera cannot be applied in thick layers, as it has a tendency to crack and peel, rarely could have the deep colour saturation that oil paintings of later days offered. Tempera colours have not darkened whereas later day oil paintings have darkened, turned yellowish and transparent with age.
Tempera has been used for murals of Egypt, Babylonia, Mycenaean period in Greece, China and early Christian catacombs. It was also used for painting interiors, mummy cases, decorative storage boxes, furniture items, papyrus rolls, altarpieces, and for illustrating manuscripts. Indian Cave (Bagh caves) paintings and interiors of architecture such as ceilings have been coated in Tempera style.
Tempera painting as art-medium was susceptible to moisture and biological degradation. It was widely used in Europe with Italy as the chief centre. Post middle ages development of oil painting system reduced its usage. Tempera system of painting as the architectural coating showed many improvements. CALCIMINE and OIL BOUND DISTEMPER are examples of such systems.
There are many recipes for making Tempera as there are methods of base surface preparations. Egg tempera is considered the most-durable form of the medium, generally, and less affected by humidity. Binders like egg yolk and white, casein, gum, or glycerine, are used, with additives like vinegar, vegetable oils. These are mixed with pigment powders or ground pastes of it.
The ground or base surface preparation was very important for Tempera painting. Plaster of Paris or gesso was applied in one or more coats. In case of wood planks after such base coats, was covered with a piece of linen cloth fixed with size (starch). This surface was coated with a gesso-grasso (heavy gesso) followed by a gesso-sotile (lighter gesso).