chrome logwood (Cr-logwood) ink

Ingredients

potassium chromate, natural logwood extract, ultrapure water

Preparation Steps

Original Recipe Text

As per (p. 4), 0.005 g of potassium chromate dissolved in 50 mL water, 1 g logwood extract added, and the solution heated for 30 minutes. This formulation is noted for not requiring a separate binder (p. 2).

Evidence

"To prepare chrome logwood (Cr-logwood) ink, 0.005 g of potassium chromate were dissolved in 50 mL of ultrapure water, 1 g of logwood extract was added, and the solution was heated for about 30 min."

Remarks

Introduced in the 19th century as a non-corrosive alternative to iron gall ink to protect metal nibs (p. 3). Analysis with a 785 nm line exhibited a low signal-to-noise ratio, but 532 nm excitation clearly showed hematein-related features (p. 12, 13). Transmission FTIR of Cr-logwood ink powder shows a strong band at ca. 1140 cm−1 assigned to residual potassium chromate (p. 13).