The invention of the tempera painting goes back to the antiquity and although it was largelly used in the greekroman art, it was in the medieval and byzantine period that assumed his crucial place in art history. During this age the egg tempera recipe was established as a common practice among the monk painters of the sacred eikones (greek for «immages/icons») or the cathedral retables.
The earliest mentionts of the use of tempera are documented in the texts of the monk Theophilus Presbyter, the artist and Giotto disciple Cennino Cennini and Armenini.
The main characteristic of the tempera is the fact that it is an emulsion: it has the ability to combine oily and watery substances that usually separate. The vehicle that enables this is the egg yolk, which unifies oils, soap, glycerin, resins and even wax with water (or, in some cases white wine). According to the basic recipe, pigments are emulsified with this mixure, water and vinegar.
The most ancient tempera recipes are the casein tempera, the roman « cera colla » (with wax and glue) and the simple glue tempera (usually made with gelatine). The best tempera support must be as white and meager as possible and the best solution is thick gypsum ground on wood panel. Most of the tempera emulsions adhere very well on this type of layers. The smoothen of the surface follows and then the guilding (in the case of an icon). The basic tempera recipe was afterwards widely modified by the addition of several ingredients such as arabic gum, linseed oil, wax and mastic resine. All this modified recipes, also known under the name tempera grassa, were passed on in the italian peninsula, where they were used and improved by the great medieval and gothic masters as Cimabue, Ducio and Simone Martini. It’s important to point out that tempera grassa continued to be widely used in the early Renaissance and the whole of the fifteenth and sixteenth cencury. In fact, many famous masterpieces of this time made by great masters as Sandro Botticelli, Fillipo Lippi, Antonello da Messina, Leonardo da Vinci, Albrecht Dürer and Raffaello were created with this method. This is one of the key secrets of their beautyfull appearance and lean but intense colouring. As Giorgio de Chirico put it: « When one askes himself, how could the old masters achieve such marvellous tonal passages, such perfect modeling, solid and in the same time vibrant, this perfect execution where each brushstroke blends without mistakes or pentimenti into the other, there is only one answer: temepra. Only tempera can give this kind of painting ». De Chirico himself used exstensively this medium, mainly in the ’20s, to produce some of his finest masterpieces. The German Arnold Böcklin is another famous artist who created some very impressive and colourfull paintings using tempera.
The first big advantage of this technique, even in the case of the fat tempera grassa, is the fast and perfect drying of the colour. Once the water evaporates, the pigments reach a high levell of luminosity and saturation. The second advantage is its meager « body ». Tempera can be thinned with water, up to the point to be used almost as watercolour. This charateristic allows a very realistic and detailed rendering of the form, even in small scale paintings. To achive this, the use of very fine sable brushes is obligatory. High quality watercolour brushes are also well suited for tempera work. The result of this kind of work can be seen in the famous portraits by Holbein, Dürer and Memling.
All these formal characteristics of this medium imply that the artist has to master drawing very well in order to achieve a satisfying result, because it is with the line that he will have to treat every element of his painting and cover his surface. Unfortunatelly, tempera colour cannot be applied as oil colour, that is in a very thick, opaque manner. Being semitransparent, tempera colours have to be applied in many thin layers and – usually by the means of hatching. This implies that the rythm as well as the direction of the brushstrokes must be perfectly controlled in order to achieve a unifying rendering of all forms and evenly cover his surface. Brushstrokes must follow the internal dynamic of each form and respect the general lines of the composition. As one can easely understand, tempera painting is not appropriate for improvisation, as it requires a solid preparatory underdrawing and a very well organised work process. Every colour scale must be fully prepared in advance and the colours themselfs must be prepared fresh every day. Temepra does not forgive mistakes and once you ‘ve started you can’t go back. All the important decisions must be taken before the actual beggining of the work : design, composition, colour schemes, general style ect. If a mistake does happen, then it’s better to clean the whole panel and start anew. Furthermore, we will see some of the most important temepra emulsions and recieps.