evolution, historical study and classification of underglaze-painted tiles in iran

tiles and tilework has developed in islamic civilization based on pre-islamic iranian art and then spread out from spain to central asia. herein, iran has played an individual role among different islamic countries and remnants of various tileworks across this wide territory are clear evidences to this claim. among different species of tiles and tile decorations, we face with specific types of tiles known as underglaze-painted tiles. this paper aimed to reveal obvious and inconspicuous values of this islamic-iranian tilework. therefore, techniques used to make underglaze-painted tiles in old text of treatise of abu’l-qasim al-kâshâni (arayis al-jawahir wa nafayis al-atayib, 8th ah /14th ad) have been investigated and recognized. based on abu’l-qasim's treatise, underglaze-painted tiles are technically divided into two types: white ground and green ground. these two groups of underglaze tiles were made up to qajar period. therefore in this paper this classification has been used besides historical investigation. materials used to make these tiles were both clay and stone-paste. there was a tendency for the use of stone-paste rather than clay. according to old recipes and recent literatures, stone-paste was made of ground quartz mixed with glaze frit and fine white clay (bentonite). colors, essentially metallic oxides, were painted on a thin quartz ground and then, based on the intended technique, were glazed with a transparent colorless or copper blue-green glaze. in second part of this paper, according to collected historical remained specimens and historic researches, evolution and development of this group of islamic tiles have been investigated. in 3th-4th ah centuries, underglaze painting technique was used to make vessels in eastern iran which is known as nishapur wares. these vessels were made of buff and red earthenware and its decorations were painted on a ground slip under a transparent colorless glaze. although underglaze painting is found on some vessels, the technique did not come into its own on tiles until the 7th-8th centuries. it was by mongol that underglaze-painted tiles were developed. in this case, appearance of small and sparse underglaze tiles between monochrome tiles facades might be seen. hence, underglaze tiles according to important identified instances from different parts of iran have been classified. based on comprehensive research and individual characterizations, underglaze tiles in three different periods can be investigated: pre-safavid (from the appearance of first instances up to safavid), safavid period, and post-safavid up to end of qajar period. materials and methods used to make body, ground, design and form, colors, type of transparent glaze, location of tiles in building and application have been studied and specified for each period. for each case, different instances in iran have been exemplified with details. before safavid, places and locations which use underglaze tiles are not specified. however in safavid and qajar periods, predominant use of underglaze tiles was on wall plinth (ezâreh) of shrines and public baths. although the material used to make tiles in pre-safavid and safavid periods was stone-paste, after that, both clay and stone-paste were used. while both white and green ground were used up to safavid period, in qajar period white ground is predominant.