Grupo de color
Anyone who has had the pleasure of going to Pompeii has seen that mosaics are a very old artistic technique that has been popular since the time of the Greeks and the Romans. The word “mosaic” comes from the Greek “Musa” which refers to the nine Muses of Greek mythology who were the protectors of the arts and sciences.
The first mosaic floors – simple geometric patterns made from black and white pebbles set in beds of mortar – are well known from the 8th century before Christ in Asia Minor and Syria. In the 2nd century before Christ the Greeks were the first to work with regularly shaped stones, the so-called “tessera”. The first naturalistic representation of hunting and theatre scenes as well as three-dimensional motifs were the result. Mosaic quickly became popular as a floor covering in the homes of the times and were as a result often made by anonymous workers.
Beginning in the 1st century B.C., the Romans developed the Greek art of mosaic further and extended its use from the floor to walls as well. For the first time, things like marble cubes, shells and smalt (melted cobalt used as a blue accent) were used. Also, coloured glass was first discovered around this time period. The upsurge of wall mosaics began with its use in Roman baths in the 1st and 2nd century A.D and subsequently led to the wonderful interiors of the early Christian church in Ravenna (Basilica of Sant´ Apollinare in Classe).
The use of glass and gold smalt first began in the early Christian mosaic art (5th to the 6th century A.D.). These extremely reflective glass stones were the ideal medium for producing an almost unending palette of colours with a correspondingly impressive atmosphere within the interior of the churches. The real masterpieces of this period include the greatest mosaic ever made in the Hagia Sophia in Instanbul and the mosaic cycle completed in St. Mark´s Cathedral in Venice in the 13th century, both of which preceded the replacement of the mosaic technique by the much more quickly realizable wall frescoes. Even though mosaic fell out of favour as a wall decoration in the following centuries, it was still very often used for making floors.
At the time of the decorating of St Peter´s Basilica by the mosaik workshop which was founded by the pope in Rome in the year 1772 and which was already able to produce glass tiles in 28,000 colours, mosaic regained a measure of respect not only because of its greater durability as compared to paintings but also because of the livliness and the stability of the colours. This effort was not concentrated on developing new artistic techniques in the making of mosaics but was really the rebirth of an almost forgotten art. They were mainly only interested in reproducing frescoes as well as paintings on panels (instead of walls) in order to insure their survival. Italy remains to this day the most important centre for mosaics in the world. Today, firms like Bisazza continue to influence the look of modern architecture as regards both interiors and exteriors through the production of mosaic tiles using industrial techniques with Murano glass as well as traditional methods by hand.
The oldest method for making a mosaic, namely laying one tile after the other on a bed of mortar, can be a very strenuous undertaking if the area to be covered is a large one. The mosaic artists in the time of Christ´s birth had already found that out and therefore developed a method which allowed the mosaic to be prepared in advance in the workshop. In that method, the front side of the tiles were glued to a paper or canvas and subsequently divided up into carriable sized pieces so that they could then be placed on fresh mortar at the site. After it had dried, the paper would then be removed by applying copious amounts of water. This method made it possible to make flatter and evener surfaces than the direct method and is to this day still employed. The disadvantage is that you are always working with a reverse image of the pattern or motif. In the newest technique, the tiles are pressed into a bed of sand or clay and likewise covered with water soluble glue and paper whereby small groups of tiles can be cut loose and applied at one time.’
Treatment: In order to, for example, create bends or small details, the glass mosaic tiles can be cut with a glass pliers; tiles made of marble or ceramic can be cut with the mosaic cutter. For occasional work, you can just use a normal pliers. When cutting the tiles, we highly recommend that you use safety goggles to protect your eyes from splinters.
Mosaic tiles can be either directly or indirectly assembled. In the direct method, the tiles themselves are each glued in their final position on the design plan which had been drawn on a substrate or transferred to it by means of GRAPHITE PAPER. If the substrate is wood, particle board, moulded fibre board or even unglazed clay, then normal WOOD GLUE will work just fine. Substrates of glass, ceramic or metal should be glued with ALL-PURPOSE GLUE. The choice of glue depends on which material is to be glued to which, whether the mosaic is to be placed outdoors or indoors or whether it will be on a floor or a wall.
In general, the direct method should be chosen when the material upon which the mosaic is to be glued is portable. (e.g. picture frames, tabletops, vases). Larger areas on walls and floors can be easily covered by using the indirect method of application.
In this process, the artwork or drawing that is the basis of the future mosaic is layed on a sturdy substrate (e.g. particle board), then a transparent plastic film (POLYETHYLENE FILM) is placed over that and finally the MESH FOR INDIRECT MOSAIC METHOD is affixed with adhesive tape. At this point, the mosaic tiles are then glued to the mesh with white glue. In doing so, care must be taken that as the tiles are pressed into place the glue does not well over. After about 12 hours, the board with the mosaic can be turned over with the help of a second panel that is placed on top to hold everything in place because this reversal will allow the easy removal of the plastic film which is now stuck to the back of the mesh. As a general rule, before doing any further work beyong this stage all the glue must be completely set.
The thus prepared mosaic can then be placed in a bed of tile glue (the thickness of which should be determined by the thickness of the tiles). A SERRATED SCRAPER is the best tool for applying the glue. Using a rubber hammer and a small board, the mosaic should be carefully pressed into place and any glue that has oozed out can be removed with a toothbrush.
After 24 hours the mosaic can be grouted. The grouting powder should be placed in a FLEXIBLE PLASTER CUP with water and stirred into a paste with the consistence of whip cream and subsequently applied to the joints with a RUBBER GROUTING SCRAPER. After the grout has dried somewhat, the mosaik should be carefully cleaned with a moist cloth. Mosaiks on the floor should be grouted in such a way that they are even and flat. Other mosaics can either be grouted or not, depending on the effect you require.