HISTORY OF PHOTOGRAPHY - CALCULATION OF EXHIBITION

HISTORY OF PHOTOGRAPHY "Vidal optical photometer", conceived by the French scholar Lteuon Vidal (24 February 1833 - 5 August 1906), inventor specialized in photographic engineering. It is a glass disk divided into twenty sectors covered by increasing layers of transparent paper; this disk was superimposed on another that carried in the margin twenty numbers dug on a black background (see FSNgilardi_73209.jpg), everything was placed inside a The disc was superimposed on another that carried in the margin twenty numbers dug on a black background (see FSNgilardi_73209 jpg), everything was placed inside a perforated box on the bottom and lid, which was pointed at the subject to look at the disc through the hole, turning it from light to dark until you find the The number that did not allow you to see anything; the number was compared with the photometric tables to determine the correct exposure. La Fotografia" by Count Luigi Gioppi of Ttesirkheim (1858 - 1930), doctor in law, Knight of the Crown of Italy, co-founder and editor of the magazine "Il Dilettante di Fotografia - Illustrated People's Journal", authoritative compiler of technical manuals disclosure of photography and essays from other disciplines, as well as holders of the magazine "Il Dilettante di Fotografia". Engraving, Milan, 1891