I was looking at a bronze glaze by [Ruth Gillet #4576] (Glazy) and amending it to use the materials I have. When I substituted manganese dioxide for manganese carbonate the resulting MnO was treated completely differently see #143794.
The carbonate in #4576 was included with R2 but the dioxide in #143794 is shown just as a colourant. I referred to Digital Fire for the adjustment from carbonate to dioxide and altered all the other materials in #4576 before I changed the carbonate to dioxide #143793, so that I could make sure the glaze was in the same general area on Stull. The glaze looked pretty similar until I changed the manganese and then it went off the Stull chart. Why are the two materials treated so very differently in the Stull analysis?