Degraded realgar

Ingredients

arsenic sulphide, realgar

Preparation Steps

Original Recipe Text

Realgar was used for yellow inks as documented in historical sources (p. 9).

Evidence

"When analysing the yellow pigments with Raman spectroscopy, we observed the peaks at 353 cm−1, 189 cm−1, 220 cm−1 and 244 cm−1, characteristic of realgar... Peaks at 231 cm−1 and 155 cm−1 could be attributed to pararealgar, which is yellow in colour"

Remarks

The yellow pigment suffered from a photo-oxidation process that transformed the originally orange realgar into yellow pararealgar (p. 5). Trace amounts of mercury were detected, likely from cross-contamination of tools (p. 4, 9). Analysis on f. 4r, ll. 2–3; f. 10r, l.5; f. 10v, l. 3.