Suillus granulatus was very tempermental to iron and tannins. The iron swatches stained as did the linen swatch mordanted in tannins and aluminium acetate. Separating the swatches in the dye bath, adding one at a time, still resulted in the same level of staining. My takeaway was that they were very sensitive. Also, it is very tricky to make a lake from Suillus granulatus. After straining the dye bath multiple times very tiny pores/tubes remained in the bath and when I added the alum and soda ash they reacted in a way that they increased in size. The liquid was not completely clear and there was very little pigment accumulated.