Postcard from New Zealand.

“Blue books” of New Zealand ferns was  produced by Herbert Dobbie (13 February 1852–8 August 1940)  in the late nineteenth century.  They were made by a process akin to blueprinting, described by Dobbie himself as “a simple form of photography or nature printing”.  A fern specimen was placed on chemically treated paper, which was then exposed to light for a set period of time.  The paper was then washed in water which caused the exposed paper to turn blue while the paper under the fern remained white.
Thank you Nicky for this  fascinating card and nice stamp.,
2018 Stamp--An iconic view of Mauao and Mount Maunganui .