Degraded verdigris

Ingredients

copper, vinegar

Preparation Steps

Original Recipe Text

The historical production of verdigris involves the use of vinegar to produce copper acetates (p. 5). The 13th-century treatise by al-Himyari refers to it as 'the green hibr' used for marking declensional endings (p. 9).

Evidence

"Therefore, we suggest that the green pigment used in this manuscript can be identified as verdigris, since degradation products compatible with its alteration have been detected with Raman spectroscopy, although its characteristic peaks were not"

Remarks

Prone to degradation involving environmental factors and binding media. Raman spectroscopy revealed organo-copper complexes and copper (I) cyanide (CuCN) as degradation products (p. 5). Trace mercury contamination suggests the same tool was used as for the red and yellow dots (p. 9). Analysis on f. 3r, l.4; f. 5r, l. 1; f. 7v, l. 4; f. 9r, l. 4; f. 10v, l. 4.