DRAPER'S FOURTH PORTRAIT LENS AND PLATE BOX IMAGE "K"

It is doubtful that before February 1840 Draper considered his ability to use optical principles to obtain portraits of the human face as anything other than a scientific method solving optical and chemical problems. Apparently in response to Morse's urging, he now agreed to adapt his earlier portrait technique into a commercial product suitable for a business like Wolcott's.[91] After the university term ended in April they opened a gallery.

Morse and Draper used a turret-room on the roof of the university building as a workshop, and built a "hastily-constructed shed, with a glass roof" as their operating room.[92] During this period of experimentation working with Morse on the roof of the university, Draper perfected his procedure with a final system of lenses incorporating technology and technique gleaned from his September experiments with four-inch lenses. At this later date, Draper fashioned his original pair of convex lenses into a more complex arrangement. The sophisticated new system maximized his stated objectives of wide aperture and short focal length. He described his final arrangement as: "Two double convex lenses, the united focus of which for parallel rays is only eight inches; they are four inches in diameter in the clear, and are mounted in a barrel, in front of which the aperture is narrowed to 3 1/2 inches."[93]

This was the lens system with which Draper took the famous portrait of his sister Dorothy Catherine: in his July 1840 letter to Herschel he described the same arrangement.[94*]



Plate "K"
[Fig. 20 credits]
 Two of the visible plates in the recently discovered ninth-size plate box may have originated during Draper's spring 1840 experimentation. Plate K depicts a man sitting indoors. There is no squint to the expression and the lens system projects adequate depth of field for a portrait (especially in comparison to plate J). The image is reversed left to right. The subject's eyes are open and clearly delineated with a bright spot of (mirror) reflected light in the corneas. This large, pupil-obliterating spot of light is found in other portraits where it is known that the operator used an early system of mirror-reflected, filtered sunlight as illumination.[95]

Draper may have taken this image with at least a prototype of the lens he perfected for operation in his spring 1840 gallery. As mentioned, his final system used two double-convex, four-inch, nonachromatic lenses, and was apparently developed from his earlier 1839 experiments with one four-inch aperture biconvex lens of 14 inches focal length. If plate K was made with such a lens, it pre-dated standardization of posing and background that may have characterized Draper's gallery products after April 1840. Plate K possibly depicts Professor Martyn Paine, Dr. Draper's colleague at the University of the City of New York. There is some visual resemblance to a later lithograph of Paine.



On left, detail of Plate "K" (reversal of the original daguerreotype is corrected),
and on right, lithograph of Paine c. 1846.
[Fig. 21 credits]


CONTINUE to
12. Plate box image "L"


BACK to
10. Morse's winter experiments


SITE MAP