Appendices - Strolling Through Istanbul: The Classic Guide to the City - page 485

lozenge capital, apparently introduced by Sinan or anyhow not much
used before his time, is a simple structure of juxtaposed lozenges.
Neither capital is very satisfactory compared with the Doric, Ionic or
Corinthian, because both, especially the lozenge, give a too-smooth,
weak transition from the cylinder of the column to the square of
the impost. In the baroque period bad imitations of western types
of capitals came into vogue, almost always hopelessly weak. And
until the baroque period all Turkish arches had been not round like
Roman ones but pointed like the Gothic, and sometimes of the ogive
or “broken” type that is often so efectively used by Sinan. It should
also be noted that the Turkish dome resembles the hemispherical
Roman, Byzantine and Syrian type, not the more common western
ovoid type invented by Brunelleschi, which is structurally double:
even when Turkish domes are double, as in some türbes, each dome
is structurally independent of the other.
Of decoration applied to architecture, far and away the most
brilliant and striking is the Turkish tiles. It was not until fairly recent
years that the full importance and uniqueness of the Turkish wares
were recognized: they used often to be called Rhodian ware or else
lumped together with Persian pottery. Even though the potters were
sometimes Persian - as well as Greek, Armenian and Turkish - the tiles
were altogether diferent from Persian ware. They were manufactured
chiefly at Iznik but also sometimes at Kütahya and Istanbul. In
Istanbul chiefly three periods of Turkish ceramics are represented.
In the early period from the Conquest to the mid-sixteenth century
we find extremely plain tiles without design, deep blue or a lighter
green or turquoise, usually hexagonal and sometimes overlaid with an
unfired pattern in gold. More interesting are the tiles in the cuerda seca
technique: instead of a painted design covered by a transparent glaze,
in these tiles the glazes themselves were coloured and the colours were
prevented from running into each other by a hair-like dividing line of
permanganate of potash outlining the design (hence the name cuerda
seca , dry cord); if visible at all this line is deepest purple or black.
The predominating colours of these tiles are apple-green and bright
yellow with subordinate blues and mauves. They are very beautiful
and very rare in Istanbul: see the description of the Şehzade's türbe