paper stacks

Evidence

"Once tannins were used to prepare inks and applied to the writing support of the mock-ups, however, they could be detected only occasionally in ATR, as they diffused in the writing support; the resulting spectra are therefore heavily influenced by the components of the paper or of gum arabic."

Remarks

The paper substrate in Arabic manuscripts often contains a high and heterogeneously spread iron content, which complicates the detection of iron-based inks (p. 183). Tannins tend to penetrate and diffuse into the paper, whereas carbon stays on the surface (p. 181).