Text quoted from The New Discworld Companion.

Chriek, Otto. Vampire iconographer with the Ankh-Morpork Times. He is thin and pale with thin, blue-veined hands an skinny black-clad legs. He wears little, oval dark glasses. Otto is a Black Ribboner - a member of the vampires' League of Temperance. He is quite an innovator in the wolrd of Discworld photography and he is working on such new processes as colour printing and the obscurograph - a camera to take pictures with Dark Light. His use of salamanders for flash pictures causes him some problems and he used to deal with this by carrying a card saying 'DO NOT BE ALARMED. The former bearer of this card has suffered a minor accident. ou vill need a drop of blood from any species, and a dustpan and brush.' Later, he refined his recovery technique by carrying a small bottle of blood on a string around his neck - this breaks on the floor if he turns to dust as a result of a salamander flash. Otto suffers for his art. He also wears the only photographer's jacket with tails. (The Truth, Reformed Vampire's Diary, Monstrous Regiment)