"For many cultures, the practicalities of ink - legibility, permanency and consistency - have gone hand-in-glove with rather more diffuse, emotional, even reverential considerations. The ancient Chinese used inks perfumed with cloves, honey and musk. The scents, it is true, helped cover the odour of the binders used - yak skin and fish intestines were common - but these inks sometimes also contained powdered rhinoceros horn, pearls or jasper. In medieval Christian monasteries, the act of copying and illuminating manuscripts, of putting wisdom and prayer to paper, was seen as a spiritual process in itself.
Black ink also had a devotional relationship with Islam: the Arabic word for ink, midãd, is closely related to that for divine substance or matter. An early seventeenth-century recipe in a treatise on painters and calligraphers contained 14 ingredients; some, like soot and gallnuts, are obvious enough, but others - saffron, Tibetan musk and hemp oil - are far less so. The author, Qadi Ahmad, was under little doubt of ink's numinous power. 'The ink of the scholar,' he wrote, 'is more holy than the blood of the martyr.' "
From the chapter 'Ink' in The Secret Lives of Colour by Kassia St. Clair.