Metallic iron particles mixed with iron oxide and gypsum

Ingredients

Fe, iron oxide, gypsum

Preparation Steps

Original Recipe Text

This blotting material is a complex mixture of metallic iron particles, iron oxide, and potentially gypsum. These black, shiny flattened particles were applied to wet ink on folio 133a to absorb excess liquid (p. 183).

Evidence

"Black, shiny flattened particles, applied to fresh ink which then transferred to particles leaving the paper surface with less ink. Purpose: blotting"

Remarks

The authors question if the Fe content is purely metallic or part of an oxide, or if it is gypsum mixed with iron oxide. The physical result of the application was the transfer of ink to the particles, effectively thinning the ink layer on the paper (p. 183).