GLW51 Wu Blue Crackle: Gloss finish, not foodsafe.
Georgie's Cone 6 Sculptural/Textural Gloss Crackle Glazes give their best and intended results when used on porcelain or tight white stoneware clay bodies. Crackle glazes ARE NOT FOODSAFE because of the nature of their fired surface.
India ink will highlight the crackle patterns of the fired glazes -- just brush on, and then wipe off of your glazed and fired pot. India ink, however, should only be used when the clay beneath the glaze is vitreous (that is, fused and waterproof as a result of firings). If the clay is not vitreous, the India ink will soak into the clay body and spread, with less-than-desirable results. If the ink soaks in, there is no cure other than refiring the piece to burn the ink out.
Georgies Glazes are formulated for application with brushes, but they can be thinned with water if your prefer dipping or pouring application.