Polychromide colour print with hand written inscription: 'From Aron Hamburger, to his friend [Major...?] Klein with admiration of his succes in "Rainbow-Chasing"...negatives made in 1912'. Aaron Hamburger's polychromide proces operated from London's Dover Street Studios from 1911 until WWI. Pfenniger's Bennetto camera was used to make separation negatives, with high intensity lights permitting exposures of 1/100 second. The prints from the negatives were made using three methods. Yellow was printed on bromide paper, bleached and chemically toned, magenta was made on coloured carbon tisue, while cyan was a cyanotype toned silver image.
© National Museum of Science & Media / Science & Society Picture Library