He stayed at the home of the owner of the company, Robert Woodhouse, as was customary for young Englishmen moving to Portugal to work in the wine trade.

He may have learned of the calotype process from Joseph James Forrester, famous for mapping the Douro river, who took up amateur photography around 1853, although information was first made available in the Revista Literária published in Porto.

[5] For more than a century, Flower's direct descendants ensured the conservation of his photographs before donating them to the National Photography Archive of the General-Directorate of Cultural Heritage of Portugal.

In 1928, his grandson, Harold M. Flower, commissioned new prints obtained from the calotypes and toured the north of Portugal to try to identify the places photographed by his grandfather.

This allowed the photographs to be appraised not just for their historical record but also for their artistic style, as noted by André Rouillé in the Exhibition Catalogue.

[6] An examination of the collection shows strong evidence of Flower's technical skills and mastery of photographic techniques as well as deliberate attempts to experiment.