Description:Lantern slide illustrating the problem known as "crazing" on the surface of a piece of ware with a porous body.
This lantern slide appears to be one of a group used for a presentation or slide show by Blake entitled “Staffordshire Pottery.” Photographed by William Blake..
A small folder containing approximately sixty reader cards was found in the same box as the slides. The cards contain information about the images. The card that appears to correspond to this slide reads;
"Crazing. Glaze covers the porous body of earthenware rendering the vessel waterproof. Unless, under changes of temperature, the glaze expands and contracts in the same ratio as the body it will crack, called crazing [sic]. Liquids can then soak into the body and the vessel will become useless."