Grand View

by Jon Burch Photography

Title

Grand View

Artist

Jon Burch Photography

Medium

Photograph - Digital Capture/textured

Description

The "Grand View" overlooks features in Colorado National Monument like the Kissing Couple, Praying Hands, Independence Monument, and Sentinel Spire. The photograph was made was made on a modern Canon 5D MkIII camera and processed to resemble an Autochrome image from an earlier film type.
The Autochrome Lumi're was an early color photography process patented in 1903 by the Lumi're brothers in France and first marketed in 1907 and was the principal color photography process in use before the advent of subtractive color film in the mid-1930's. The process created images on a glass plate using combined layers of dyed potato starch grains.
Autochrome is an additive color "mosaic screen plate" process. The medium consists of a glass plate coated on one side with a random mosaic of microscopic grains of potato starch dyed red-orange, green, and blue-violet - a functional variant of the standard red, green, and blue additive colors - which act as color filters. Lampblack fills the spaces between grains, and a black-and-white panchromatic silver halide emulsion is coated on top of the filter layer. Unlike ordinary black-and-white plates, the Autochrome was loaded into the camera with the bare glass side facing the lens, so that the light passed through the mosaic filter layer before reaching the emulsion. The use of an additional special orange-yellow filter in the camera was required, to block ultraviolet light and restrain the effects of violet and blue light, parts of the spectrum to which the emulsion was overly sensitive. Because of the light loss due to all the filtering, Autochrome plates required much longer exposures than black-and-white plates and films, which meant that a tripod or other stand had to be used and that it was not practical to photograph moving subjects. The plate was reversal-processed into a positive transparency was first developed into a negative image but not "fixed", then the silver forming the negative image was chemically removed, then the remaining silver halide was exposed to light and developed, producing a positive image. Each starch grain remained in alignment with the corresponding microscopic area of emulsion coated overcoat. When the finished image was viewed by transmitted light, each bit of the silver image acted as a valve, allowing more or less light to pass through the corresponding colored starch grain, recreating the original proportions of the three colors. At normal viewing distances, the light coming through the individual grains blended together in the eye, reconstructing the color of the light photographed through the filter grains.
To create the Autochrome color filter mosaic, a thin glass plate was first coated with a transparent adhesive layer. The dyed starch grains were graded to between 5 and 10 micrometers in size and the three colors were thoroughly intermingled in proportions which made the mixture appear gray to the unaided eye. They were then spread onto the adhesive, creating a layer with approximately 4,000,000 grains per square inch but only one grain thick. The exact means by which significant gaps and overlapping grains were avoided still remains unclear. It was found that the application of extreme pressure would produce a mosaic that more efficiently transmitted light to the emulsion, because the grains would be flattened slightly, making them more transparent, and pressed into more intimate contact with each other, reducing wasted space between them. As it was impractical to apply such pressure to the entire plate all at once, a steamroller approach was used which flattened only one very small area at a time. Lampblack was used to block up the slight spaces that remained. The plate was then coated with shellac to protect the moisture-vulnerable grains and dyes from the water-based gelatin emulsion, which was coated onto the plate after the shellac had dried. The resulting finished plate was cut up into smaller plates of the desired size, which were packaged in boxes of four. Each plate was accompanied by a thin piece of cardboard colored black on the side facing the emulsion which was to be retained when loading and exposing the plate and served both to protect the delicate emulsion and to inhibit halation.
The 1906 the U.S. patent describes the process more generally stating that the grains can be orange, violet, and green, or red, yellow, and blue or any number of colors, optionally with black powder filling the gaps.

The image was made from a pull out on Rimrock Drive near the Fruita, Colorado entrance to Colorado National Monument. Copyright 2013 Jon Burch Photography

Uploaded

August 14th, 2013

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