smalt

Ingredients

blue fibres, yellow-brown fibres, smalt, cobalt

Preparation Steps

Original Recipe Text

Blue-grey paper was found containing blue particles, likely smalt (blue glass with cobalt). Fibers found include light blue, dark blue, and yellow-brown varieties of different lengths (p. 175).

Evidence

"Blue-grey paper, but without blue fibres. Small brown fibres homogeneously distributed. Blue particles (probably smalt) present... smalt particles consist of blue glass, containing cobalt."

Remarks

In Or. 6333, the blue dye may have been added to the pulp, and smalt particles provide the color (p. 175). Higher iron content in some papers (Or. 25.745) was attributed to the presence of blotting sand particles rather than the paper pulp itself (p. 175). High calcium content in Or. 25.744 points to good paper quality (p. 176).