Why does my tin white glaze have a pink tinge?

This fault is caused by volatilisation during the firing and may produce a variety of other undesirable effects.In the case of the example, the tin white glaze has absorbed chromium fume form the kiln atmosphere to produce a chrome-tin pink. The chromium has volatilised most likely from a chrome decorated pot somewhere else in the kiln. All materials volatilise to some extent during the firing and so the kiln atmosphere is always laden with ‘fume’ which can sometimes be absorbed by other pots. This effect can cause a significant problem to producers of tableware when items glazed with unleaded glaze, which would otherwise be compliant with regulations, are fired at the same time as leaded glazes, particularly when copper decoration is used on any item. Where volatilisation problems arise, the only satisfactory treatment is to ventilate the kiln atmosphere more effectively. This can be achieved by using a lighter packing density, removing the top vent plug for a longer time period during the firing, or installing a kiln ventilation system to draw in fresh air and remove the fume to outside atmosphere.