Dark Ink

Dark ink is a writing pigment favoured by well-resourced scribes and writers in the Eleven Cities for documents that are either valued, intended to be read by prestigious or esteemed readers, or to last a long time. It is itself esteemed for its glossy dark colour, smoothness of application, and resistance to fading.
Most documents in the Eleven Cities are written using bark-based or other vegetable-derived inks. These tend to be dark brown in colour, though soot is sometimes added to turn them black. Dark ink - so called by those who use it to distinguish it from 'black ink' which contains soot - is instead derived from an animal source - specifically, octopuses. These eccentric sea creatures possess two glands, one producing mucus and the other a very dark pigment, which they combine into a thick black liquid and squirt at predators and other creatures who harass them. This liquid is the dark ink. Purchased in much smaller quantities than most other inks, it is applied with special brushes rather than a common quill. Scribes also praise it for the fact that unlike vegetable inks it can be diluted to transparency (effectively, erased) by the careful application, usually via pipette, of seawater.
Octopuses cannot be fished for this substance normally, since the distress of being hooked or netted is exactly the sort of occasion upon which they will expel their ink, leaving it to disperse uselessly in the seawater around it. They are highly curious animals, however, and can be lured into pots baited with food in much the same way as crabs or eels. The complication here is that those animals can be captured in basket-like pots, whereas the octopus, which has no bones and appears to be highly intelligent, can squeeze through very small gaps and thus escape such captivity.
The capturing of live octopuses therefore requires literal glazed clay pots, a yard or so in diameter, with narrow necks and smaller holes near the bottom sealed with tight bungs. Baited with crab meat or similar, these pots are submerged in the rocky shallows octopuses frequent with their mouths a foot or less from the surface. The trapper will typically submerge a few of these at once, then watch them closely over several hours. Should an octopus enter one, the neck is quickly sealed with another tight bung, and the pot manhandled out of the water onto a boat or the shore, where the smaller aperture opened for as long as it takes for the water to drain before being sealed again. Octopuses can survive out of water for longer than most sea creatures but will eventually suffocate without ever seeing the threat at which they might have shot their ink. The fisher can then retrieve the dead animal from the pot, carefully drain its two glands, and mix their products together into dark ink. 
Dark ink is similar in concept to the Sapphire ink gathered from the altogether more dangerous hunting octopuses that haunt the seas near the northern cities, though it is much less dangerous to gather and thus significantly more common. It fetches impressive prices, however, partly because the labour-intensive process of gathering it means demand tends to outstrip supply. The Commercial Guilds in Chogyos, Elpaloz and Tyros are known to specifically employ minor functionaries on worthwhile wages to collect the ink on a full-time basis, and thus maintain a good supply for their organisation. Others who wish to use it must purchase it on the open market, where it is not always available.

Type

Biomaterial