Leon Van Loo (1841–1907) was an American photographer and art promoter.
Born 12 August 1841, in Ghent, Belgium, he moved to Cincinnati, Ohio in 1858, when he opened a photography gallery.
He subsequently spent time travelling to Europe and collecting art, which he displayed in Cincinnati.
Photographs using this technique are printed on zinc oxide applied to blackened sheet-iron and present a pearly, transparent surface.
In 1890, he was a founding member of the Cincinnati Art Club and served as president from 1894 to 1896 and 1903–1904.