Scarva GZ2108 Zinc Free Multi-Purpose Leadless Earthenware Transparent From  £11.28

This glaze did not work at all over the spectrum black and blue colours and I lost a huge amount of work . I have used it before so didn’t do a proper tester , which was bad.Don’t use it without testing and don’t use it over black or royal blue underglaze as it crazes and goes milky. Very stressful.