I too have experienced the same issue with white clay firing yellow -ish under clear glaze. Ugh, so frustrating. While I'm not using Standard's white slip I do work with their white earthenware (STD 105). I recently discovered that same document from Standard (https://cdn.shopify.com/s/files/1/0039/8177/0841/files/105-LFW_Glaze_Rec.pdf?v=1674848426) and find it interesting. I've been using Mayco/Duncan PB001 which is on the list as compatible (crystal clear at cone 04) but it wasn't for me. That said... I did test the Spectrum 700 and was happier with the results. The clay is definitely whiter under that clear glaze. I bisque and glaze to 04.
tinypieces got a reaction from Hulk in Clear glaze looks yellow
