İznik
A famous glaze (İznik çinisi): its traditional recipe or analysis, its firing, and a version from the materials sold where you are.
About İznik
The clear, brilliant glaze of Ottoman İznik ware, laid over a white quartz-frit body and slip painted in cobalt blue, turquoise, green and a raised bole red. Analyses of sherds agree that it was a lead-alkali glaze, rich in silica and soda, with a quarter to a half of its weight lead oxide and some tin oxide. It is shown here as history: its analysis, not a recipe to mix.
- Native name
- İznik çinisi
- Where
- İznik (Nicaea), Bursa Province, Türkiye
- When
- Ottoman, about 1480–1600
- Firing
- 950–1050 °C; oxidation
Whitebodied wares were fired at about 950–1050 °C; the glaze matured below about 1000 °C.
History only: this glaze was made with lead. Its analysis is shown as history, not as a recipe to mix. The version below is a different glaze, without lead.
Historic analysis
Weight percent, the middle of the ranges Colomban and colleagues give (SiO2 45–47, Na2O 8–14, K2O and CaO about 1, PbO 25–30, SnO2 4–7). Okyar found 30–40% lead oxide and 2–12% tin oxide, mostly dissolved, and one group of about 50% lead oxide with no tin.
| Oxide | Weight % |
|---|---|
| SiO₂ | 46 |
| Na₂O | 11 |
| K₂O | 1 |
| CaO | 1 |
| PbO | 27.5 |
| SnO₂ | 5.5 |
Lead-free version
A different, lead-free glaze in the İznik style: the analysis above with its lead's share of the fluxes handed to soda, lime and boron, for cone 04–02 (about 1060–1120 °C) in oxidation, over a white body or a quartz-rich slip, with 6% tin oxide. It is a calculation, not a copy of the old glaze, and the bole red cannot be matched.
Calculated, not yet test-fired. Fire test tiles before you use it on any ware, and test a food surface for leaching.
Try it
Safety
The historic glaze holds 25–50% lead oxide. Glazecalc shows its analysis as history only and offers no lead material or recipe for it. Lead glazes can leach lead into food and drink, and raw lead compounds are poisonous to handle, breathe or fire.
Sources
- Colomban Ph. et al., "On site Raman analysis of Iznik pottery glazes and pigments", Journal of Raman Spectroscopy (preprint arXiv:cond-mat/0612375, 2006), section 3.6.Open(read 2026-11-04)
- Okyar F., İznik keramiklerinin karakterizasyonu (The characterisation of İznik ceramics), PhD thesis, İstanbul Teknik Üniversitesi Fen Bilimleri Enstitüsü, 1995 (advisor E. Geçkinli); thesis record and abstract.Open(read 2026-11-04)
- Tulun T., Döner G., Çalışır F., Çini N., Karatepe N., Meriçboyu A., Tekin A., Altun A., Arlı B., Arlı H., "An archaeometric study on ancient Iznik ceramics", Balıkesir Üniversitesi Fen Bilimleri Enstitüsü Dergisi 4(2), 2002, pp. 34–40.Open(read 2026-11-04)