A short video showing principles of the Stull Chart used in Glazy.org and how to manipulate glazes. Using the 1:5 matte line and the 1:7.5 Best Gloss line to move your glaze from matte to glossy or glossy to matte as well as following the 1:7.5 line up the Best Gloss. A bit of phase diagrams, firing cone variation, effect of clay body, etc. (Part 4 in series)