Sentence:  How, then, do bibliographers and historians find out about the technologies of exotic illustrative processes like <WSD>acrography</WSD>, butterfly-wing printing, gypsography, selenotype and the "Via sicca" process? 
Meaning of the word marked with <WSD> tags:  A method of relief etching on wood, metal, or stone by means of a coating of compressed chalk, invented by Louis Schonberg in 1841.