Dufaycolor transparencies, made by lily specialist and plant hunter Henry Frederick Comber, are one of many interesting finds in the Lindley Library

While scanning a selection of lily portrait transparencies, I was curious to find out a little more about this now
obsolete photographic process called ‘Dufaycolor’.
Popular in the early to mid-1900s, Dufaycolor was an
additive colour transparency film process. Light would pass by a pattern on the film, consisting of three colours - red lines, and blue and green squares - that would creating a mosaic effect, technically called a ‘reseau’. When viewed from a distance, the
pattern would merge in the eye of the viewer, to create the full spectrum of hues.
Making movies
Although there are over a million squares of colour per square inch, the technique could still be
visible on a projector, due to a high level of magnification. So Dufaycolor was
better suited to motion picture, which became popular too, including the early film
A Colourbox (1935) which was processed in Dufaycolor but used a technique of painting directly onto the film.
Aid to plant recording
The RHS Historian Dr Brent Elliott told me that this collection of transparencies actually belonged to
Henry Frederick Comber, an important 20th century plant collector who specialised in the study of lilies. Comber first went on an
expedition to the Andes for two years, visiting Argentina and Chile. He
later visited Tasmania, where he collected seeds of 147 different varieties of plants, though the germination of the seeds was not always successful. He published an article
‘Some Glorious Failures’ in
The Gardener’s Chronicle, documenting his efforts.
In print
Some of the lily transparencies are printed in the
RHS Lily Year Book, and in
Modern lilies by M.J Jefferson Brown (1966), which include Comber’s classification of lilies.

These transparencies are just some of the rare and unusual items held in the
Lindley Library photographic archive. We are lucky enough to have a very large collection of prints, transparencies and slides, many of which demonstrate interesting
historical photographic techniques including: auto chromes, daguerreotypes, stereo slides, albumen prints and glass lantern slides.
More information
RHS members can borrow from the thousands of gardening books held in the Lindley Libraries - visit our online catalogue.
Even if you are not an RHS member, the RHS Lindley Libraries are open to everyone and provide access to modern collections of books and journals on gardening and related topics. Our heritage collections of rare books, photographs, art and archives are accessible by appointment.