Question

question 18
who invented the cyanotype in 1842?
hippolyte bayard
henry fox talbot
sir john herschel
henry peach robinson

Explanation:

Sir John Herschel invented the cyanotype in 1842. Cyanotype is a photographic printing process that gives a cyan - blue print. Herschel was a prominent scientist and inventor in the field of photography.

Answer:

C. Sir John Herschel