The organic pigments divide itself into two sub-groups: one of vegetable and the other of animal origin. All the same with the inorganic pigments which are also divided in natural and artificial pigments.
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaback

Here is a short definition of the techniques mentioned in the files:

Fresco : a technique which usually employs pigments diluted in water and painted directly onto the wall. We are not certain about its origin though it is generally attributed to the Greeks. Still, the wall paintings in Ercolano and Pompei in the south of Italy, are a matter of scholarly discussion. It is thanks to the Florentine artist Masaccio that fresco became fashionable again and thus remained throughout the XVI and XVII centuries in Italy

Tempera : the word refers to the techniques which employs animal, vegetable glues or synthetic medium as binders. Before Cennino Cennini, i.e. the XV century, `tempera' referred to the mixtures of the pigments with animal glues whilst at Cennini's time the egg yolk came largely into use. It was to become a typically Italian mixture used throughout the Renaissance period.

Oil painting : techniques which use as medium siccative or fixed oils, and essential or volatile oils. These can mix well with pigments and dry when in contact with the air. Scholars maintain that the oil techniques had already been in use at the time of ancient Greece and employed on walls. Therefore, Vasari's statement that it had been the Flemish painter Van Eyck to discover oil painting has to be regarded as imprecise. Van Eyck however contributed to improve the oil technique.


Encaustic painting : this is the name given to all the techniques which employ wax mediums. They are not to be confused with the modern wax painting where oil colours are mixed with melted wax in turpentine without being heated up as it happened in the traditioanl procedure.

The stability to the light, and humidity and lime is calculated in an empirical way. The one reported here is the result of the comparison between different texts, and will be represented as follows:

scanty		low		medium		good		excellent

The refraction index shows the relation between the light speed in the air and the speed of the light in the pigment. The higher is the refraction index the higher is the colour opacity.

Poisonous soustances : many pigments are poisonous and/or toxic so that it is good advise to be cautious when preparing and using the colours. It is safer to handle them with caution using gloves and masks against powders.

The pages on the topic `colours' are numbered in progression and have been grouped on the basis of their pigments in this order:

Oranges, Blue, White, Brown, Yellow, Black, Red, Green, Violet.

Essicative (or fixed oils)[top]

These oils can breath oxygen and once applied on a surface they form a solid and elastic layer. More important to the oil painting techniques are linen seeds oil, poppy and walnuts oil. Others such as egg oil and amber oil are no longer used. Olive oil is used instead for the conservation of brushes.


s
Essential oils (OR volatile oils) [top]

Volatile substances have a strong aromatic smell and come from certain parts of the tree and also from minerals such as petroleum. The basic essences used for painting are pure gum turpentine, and petrol essence. There are also lavender essence, spike-lavender, rosemary, and carnation essence. Volatile oils give a great fluidity to the oil colours while using them, but they often become yellow and thick once dried.


s
Waxy mediums [top]

Wax mixed with colours has been successfully employed since ancient times. Egyptians appear to have used it melted in with naphtha. There are different kinds of waxes. The most famous is bee wax, although there are other similar substances such as vegetal wax from impermeable tree barks, and mountain wax from certain woods. In order to be used in painting wax is usually whitened and purified with either natural or chemical procedures.

s
animals and vegetables glues [top]

Many painting recipes used for tempera and gouaches are prepared with different varieties of glue. Glues are strong and viscous substances. Amongst the animal ones there are bone and skin and fish glues. For tempera colours best are rabbit glue and fish made not to rotten. Vegetal glue have a base of gluten: flour, amid, rice, or wheat. You can also paint with blood serum and with casein glue (a derivative from milk), or egg albumin.

s
Synthetic binders [top]

Synthetic mediums are a fairly recent invention. For instance in tempera colours synthetic binders are acrylic emulsions or synthetic resins as copolymers with a base of ether or metile. Also chetonic resins, alchidic or epossidic resins, etc. mixed with the right quantity of pigments.