Manufacture of Ancient Greek Pottery

Ancient Greek pottery, the pot­tery of An­cient Greeks, is im­por­tant to us firstly for the in­trin­sic beauty of its forms and dec­o­ra­tion and secondly, for the light it sheds on the de­vel­op­ment of Greek pic­to­r­ial art.

Be­cause fired clay pot­tery is highly durable —and few or no Greek works in wood, tex­tile, or wall paint­ing have sur­vived— the painted dec­o­ra­tion of this pot­tery has be­come the main source of in­for­ma­tion about the process whereby Greek artists grad­u­ally solved the many prob­lems of rep­re­sent­ing three-di­men­sional ob­jects and fig­ures on a flat or curved sur­face.

The large num­ber of sur­viv­ing ex­am­ples is also the re­sult of a much wider re­liance on pot­tery ves­sels in a pe­riod when other ma­te­ri­als were ex­pen­sive or un­known.

Ancient Greek pot­tery ves­sels was used by the Greeks pri­mar­ily to store, trans­port, and drink such liq­uids as wine and wa­ter. Smaller pots were used as con­tain­ers for per­fumes and unguents.

Manufacture of Ancient Greek Pottery
Ancient Greek pottery techniques

Con­struc­tion

Clay powder

The process of mak­ing a pot and fir­ing it is fairly sim­ple. The first thing a pot­ter needs is clay. When clay is first dug out of the ground it is full of rocks and shells and other use­less items that need to be re­moved. To do this the pot­ter mixes the clay with wa­ter and lets all the im­pu­ri­ties sink to the bot­tom. This is called levi­ga­tion or elu­tri­a­tion. This process can be done many times. The more times this is done, the smoother clay be­comes.

A potter's wheel

The clay is then kneaded by the pot­ter and placed on a wheel. Once the clay is on the wheel the pot­ter can shape it into any of the many shapes shown be­low or any­thing else he de­sires.

Ancient Greek pottery pots were usu­ally made in sec­tions such as the body and feet and spout. Even the body, if it were larger than 20 cen­time­ters, might be made in sep­a­rate sections and glued to­gether later with a thin wa­tery clay called slip. Af­ter the pot is made then the pot­ter paints it with a very pure black slip (made from the same clay) and a brush.

Ancient Greek pottery, un­like to­day's pot­tery, was only fired once, but that fir­ing had three stages. Af­ter the pot­tery is stacked in­side the kiln our pot­ter can start the first stage. He heats the kiln up to around 800°C with all the vents on the sides open to let air in. This turns the pot­tery and the paint red all over. Once the kiln reaches 800°C the vents are closed and the tem­per­a­ture is raised to 950°C and then al­lowed to drop back to 900°C. This turns the pot­tery and the paint all black.

The pot­ter then starts the third and fi­nal phase by open­ing the vents and al­low­ing the kiln to cool all the way down. This last phase leaves the slip black but turns the pot­tery back to red. This hap­pens be­cause when the clay is given air it turns red, but when the black slip is heated to 950°C it no longer al­lows air in. So the slipped area stays black while the bare ar­eas stay red.

Wheel made pot­tery dates back to roughly 2500 BC where be­fore the coil method of build­ing the walls of the pot was em­ployed. Most Greek vases were wheel­made, though as with the Rhy­ton mould-made pieces (so-called "plas­tic" pieces) are also found and dec­o­ra­tive el­e­ments ei­ther hand formed or by mould were added to thrown pots.

More com­plex pieces were made in parts then as­sem­bled when it was leather hard by means of join­ing with a slip, where the pot­ter re­turned to the wheel for the fi­nal shap­ing, or turn­ing. It was then slipped and in­cised ready for the kiln.

Dec­o­ra­tion and fir­ing of Ancient Greek pottery

The strik­ing black slip with a metal­lic sheen, so char­ac­ter­is­tic of Greek pot­tery was a fine sus­pen­sion (col­loidal frac­tion) of an il­litic clay with very low cal­cium ox­ide con­tent which was rich in iron ox­ides and hy­drox­ides, dif­fer­en­ti­at­ing from that used for the body of the vase in terms of the cal­cium con­tent, the ex­act min­eral com­po­si­tion and the par­ti­cle size. This clay sus­pen­sion was most prob­a­bly col­lected in situ from spe­cially lo­cated il­litic clay beds that pro­duced spon­ta­neous col­loidal dis­per­sion in rain wa­ter.

Gas operated pottery kiln

The sta­bil­ity of the chem­i­cal com­po­si­tion of the At­tic black slip ar­gues against the use of added def­floc­u­lants such as wood or other plant ashes, urea, tan­nins, even blood, sug­gested by sev­eral au­thors dur­ing the 20th cen­tury. This clay sus­pen­sion was thick­ened by con­cen­tra­tion to a paste and was used for the dec­o­ra­tion of the sur­face of the vase. The paint was ap­plied on the ar­eas in­tended to be­come black af­ter fir­ing.

The black color ef­fect was achieved by means of chang­ing the amount of oxy­gen pre­sent dur­ing fir­ing. This was done in a sin­gle cy­cle, in a process known as three-phase fir­ing.

First, the kiln was heated to around 920-950°C, with all vents open bring­ing oxy­gen into the fir­ing cham­ber and turn­ing both pot and slip a red­dish-brown (ox­i­dis­ing con­di­tions) due to the for­ma­tion of hematite (Fe2O3) in both the paint and the clay body. Then the vent was closed and green wood in­tro­duced, cre­at­ing car­bon monox­ide which turns the red hematite to black mag­netite(Fe3O4); at this stage the tem­per­a­ture de­creases due to in­com­plete com­bus­tion.

In a fi­nal re­ox­i­diz­ing phase (at about 800-850 °C) the kiln was opened and oxy­gen rein­tro­duced caus­ing the un­slipped re­served clay to go back to or­ange-red. In the pre­vi­ous phase, chem­i­cal com­po­si­tion of the slipped sur­face had been al­tered, so it could no longer be ox­i­dized and re­mained black.

An excellent video from the Getty will show you the making of a greek pottery.

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