Mosaic: a brief outline of mosaic technique and history
The making of mosaic is a very ancient artistic expression, which appeared in numerous continents: Peruvian or Mexican mosaics in turquoise, jade, gold, pearls or shells in the pre-Columbian period; jade mosaics in China during the Han dynasty (150-113 a.C.); mosaics made of turtles, shells and feathers in Oceania; mosaics made of pearls and shells in Africa; mosaics made of terra cotta in Afghanistan…
Some archaeological researchers have discovered important remnants -important both in quantity and quality- dating from the Sumerian period (III millenary BC). Other populations from the Antique period used mosaics: in Greece and Sicily, from the V century BC, mosaics on pavements with figurative or geometrical designs have been found. They were first made of pebbles and later cubic stones. During the Alexandrine period, mosaics were highly prevalent in countries of Hellenic culture.
Then, Roman Art flourished and influenced the mosaics technique from the II century BC. Mosaics were then diffused throughout the Empire’s provinces. The classic Roman mosaics, in their different periods and aspects continued to be used until the VI century AD.
The Paleo Christian mosaics started to develop from the Constantine edict (313 AD): employed mainly as wall ornamentation, they were characterized by the use of gold and colours rather than the pale Roman pavements in marble.
During the Middle Ages, Christian Art used mosaics according to the following different styles: Paleo Christian, Byzantine, Roman and Gothic and some fabulous masterpieces were created.
In Orient, Islamic iconoclast developed the incrustation of geometrical designs whereas in Jewish Art incredible mosaics were created in the VI century.
During the Middle Ages, Christian Art also demonstrated some figurative pavements in marble mosaics and geometrical settings.
In the West, Antique mosaics are mainly characterized by the two most common styles: Roman and Byzantine.
Contemporary mosaics include a whole varied set of techniques and esthetic criteria: from industrial mosaics to handmade crafts.
The first tesserae in standard dimensions appeared: they were designed to be laid besides one another in the simplest way and this was the start of the industrial mosaics.
Specifics of roman mosaics
In the Antique period, the Romans created a codification for the different tesserae, called ‘opus’. Some examples:
- Opus lapilli: mosaics made out of pebbles;
- Opus tessellatum: tesserae of a cubic shape and thickness of about 1cm maximum. They were used for the creation of geometrical designs and borders;
- Opus sectile: mosaics made for pavements with large tesserae, obtained from a very precise geometrical cut;
- Opus musivum: mosaics used for wall dressings and sometimes made of glass mosaics;
- Opus incertum: mosaics made of tesserae cut in an irregular way.
Mosaic application methods
There are three main techniques:
The indirect or ‘Reverse’ method used to cover large surfaces, mainly outdoor: the right side of the tesserae is glued onto a fabric, forming different pieces of a mosaic. Then the whole mosaic is fixed in the cement, in the permanent location;
The direct method, which consists in placing the tesserae, section by section, directly into a permanent binder of cement or other adhesive;
The direct method on temporary stucco: This is the method used to create Antiques copies. Mosaics are first inserted on a temporary bed of lime and lifted from their temporary base with a glued fabric, to be later fixed onto the permanent binder.