Roman Pottery Lamps
Pottery lamps were used as a source of light by all Romans. Artificial light was common throughout the Roman Empire, and pottery oil lamps offered an alternative to candle light. Candles, made from beeswax or tallow, were cheaper to buy but do not survive as well.
Pottery lamps functioned by adding oil through the central hole, and burning a wick placed into the nozzle area. Wicks were commonly made from pieces of linen, but could also be made from flax or papyrus.
Although there are some known areas in Britain of lamp manufacture, many of the lamps found here would have been imported from areas such as Italy, Gaul (Ancient France), Germany and North Africa. The number of lamps found in Britain is much lower than in other parts of the Empire and this is thought to be due to the cost of importing olive oil. Oil, made from olives or other vegetables, was a valuable resource and as such the cost involved in burning oil, which could otherwise be used as fuel, is thought to have been too great for widespread use of the lamps in Roman Britain. Use of these lamps in Britain was especially popular amongst the army.
Pottery oil lamps were made in three different ways. They could be handmade, wheel made, or made by mould. The use of moulds became increasingly popular, but again consisted of two different methods. Once made, a mould could be used to create many lamps, which meant that lamps could be easily and directly reproduced. This also ensured that the manufacturing of lamps could be extremely efficient and organised, producing large volumes of goods with a standardised quality.
Moulds could be made from either clay or plaster. Roman lamp makers preferred the use of plaster moulds but both types had advantages and disadvantages. For example, a clay mould would require firing whereas a plaster mould could be left to dry. However, plaster moulds also wore out quickly, as the surface would deteriorate through repeated use.
It is possible to determine whether a lamp was made with the use of a plaster mould. These moulds would often contain air bubbles, created during its manufacture. These air bubbles would create raised bumps which were pressed into the clay.
To use a mould, clay would be pressed into both halves, with any extra clay cut off at this point. The maker would then press the two sections together and leave them to dry. Once dry, the two sections of the mould would be removed. Where the two pieces of clay met, wet clay could be added to ensure the join was neat. Also at this stage, the required holes would be pierced into the clay. These holes could become the filling hole, the wick hole or an air hole. A handle could also be added if this had not been part of the main body. The lamp would then be left to air thoroughly before a glaze could be applied and finally the lamp could be fired.
A simple and early form of lamp was the cocked-hat type. This was created by producing a shallow bowl or plate and folding in the edges whilst the clay was still wet. Many fired clay lamps came in basic shapes, with round or oval bodies. In addition to these, more elaborate lamps could be found, with lamps in the shapes of animals and human parts such as the head or feet, among others. The museum holds a lamp in its collection in the shape of a bird, complete with a flower design on the head of the animal. The tail of the bird contains the hole for the wick to be placed. Other variations in style could include the number of nozzles. Lamps with several nozzles could hold several wicks, thereby producing more flames and more light.
Levels of decoration on lamps could vary enormously, and depend upon the date of manufacture but also upon limitations created by the shape and size of the lamp itself. Some lamps contained a large central circular area which contained the filling hole. This area allowed space for decoration, with scenes ranging from everyday activities, to entertainment such as gladiatorial scenes, to depictions of common myths. In addition, more simple decoration could be added through the use of raised circles and dots around the central hole.
Glazes were often applied to lamps of Roman origin. Although these glazes could contribute to the final colour of the pot, they were not generally used for decorative purposes. Instead they served a useful function, as the addition of the glaze ensured that the lamp was more watertight. Most glazes used were in fact simple slip coverings, washed on to the pot and would vary with the location of lamp manufacture, as did the clay itself used for the construction of the main body of lamp. They could be applied by painting on the slip, pouring the slip on the lamp, or by dipping the lamp. This dipping technique often could result in lamps with finger marks, showing where they were held during this process.
Plain and undecorated lamps would be cheaper to produce and to purchase. These types are more often found in military zones.
For the production of lamps, a vertical kiln would typically be used. This would contain a circular fuel chamber with a flue on one side. Above this chamber there would be a firing floor. This would contain a number of holes to allow any hot air to enter. The ceiling would be domed and built up from clay each time the kiln was used. The dome would then be broken in order to retrieve the newly made clay lamps.
Use by archaeologists
Pottery lamps are extremely useful finds on archaeological sites. Due to the ability to date pottery through closely studying the material, styles and material of lamps, archaeologists are able to gather much information about them and other finds. As clays varied depending upon the location, a lamps appearance could also vary. By looking at the colour, texture and the presence of any grit in the clay, archaeologists are able to assess where the lamp was produced.
They also allow an insight into the culture of the empire, and through their different styles allow a glimpse into the social status of the users.
Information compiled by Elizabeth Faley.