A selection of ceramics through the ages (5 second delay) Ashmolean Museum of Art and Archaeology
PotWeb: Ceramics online
@ the Ashmolean Museum

People and their collections

Robert Plot 1640-96 - scientist & antiquary

Plot and pottery (7): glazing the vessels

In The Natural History of Stafford-shire (1686) Robert Plot summarises (p 123) how pots were lead-glazed, which is of utmost interest to archaeologists and potters attempting to replicate these wares:

'After the vessels are painted, they lead them, with that sort of Lead-Ore they call Smithum, which is the smallest Ore of all, beaten into dust, finely sifted and strewed upon them; which gives them the gloss, but not the colour; all the colours being cheifly given by the variety of Slips, except the Motley colour which is procured by blending the Lead with Manganese, by the Workmen call'd Magnus. But when they have a mind to shew the utmost of their skill in giving their wares a fairer gloss than ordinary, they lead them then with lead calcined into powder, which they also sift fine and strew upon them as before, which not only gives them a higher gloss, but goes much further too in their work, than Lead-Ore would have done.'

Plot's description of the use of lead ore, lead mixed with manganese, and calcined lead as powders dusted onto the pots has been the subject of much modern debate, not least because of the severe risk to the potter's health!

Analysis of Cistercian ware and blackware glazes (Barker 1986) shows that the dark brown colour was drawn from iron in the body of the pot, so the glaze does give more than the gloss.

Slip-coated Blackware and Mottled Coloured Glazed Ware

Slip-coated Blackware and  Mottled Coloured Glazed Ware

Throwing, slip-coating and
decorating pottery

Plot and Pottery

The placing of pottery vessels
in the kiln

Robert Plot: case study
© Copyright University of Oxford, Ashmolean Museum, 2005
The Ashmolean Museum retains the copyright of all materials
used here and in its Museum Web pages.
last updated: jcm/16-dec-2005