Solar camera

The intensity of the light, and heat, they transmitted and concentrated through condensers can be gauged from reports of near loss of life when a fire started from a late version of the device, built in to a darkroom, was left unattended and still open to full sunlight.

An antecedent was the solar microscope of c.1740,[5] employed in experiments with photosensitive silver nitrate by Thomas Wedgwood and Humphry Davy in making the first, but impermanent, photographic enlargements.

Their discoveries were published in June 1802 by Davy in his An Account of a Method of Copying Paintings upon Glass, and of Making Profiles, by the Agency of Light upon Nitrate of Silver.

Jacob Wothly of Aachen improved Woodward's design with a reflector and condenser of one metre (39 inches) diameter and a focus of two meters (about 6½feet), attracting much attention, and presented it to the French Academy of Sciences, October 8, 1860, and at the Societe Francaise de Photographie in early November 1860, selling the design to Disderi, reportedly for 20,000 francs soon after, who was awarded a medal for his enlarged photographs at the 1862 London International Exhibition.

[13] Further adjustments to the original design included a clockwork heliostat, such as that invented by Léon Foucault in 1862 and built by his son-in-law, to rotate the mirror in synchronisation with the Sun's passage to concentrate its light on the condenser lens.

The calling-card format carte de visite was gaining popularity in the late 1850s, but there was increasing demand for larger portraits, which were normally contact printed from larger negatives, requiring an unwieldy lens and camera, an inconvenience which, professionals concluded, was "not repaid by a proportionate increase in the size and sharpness of the picture obtained; and that it is more practicable to obtain extra-sized pictures by enlarging with a solar camera.

Claudet, at the British Association for the Advancement of Science in October 1862, was reported as having; "exhibited last night a number of cartes de visite enlarged by the solar camera, showing the great perfection of proportion and the natural expression which may be impart to portraits when they are taken in a very short sitting, and with the apparatus placed at a proper distance from the persons, as is the case for small pictures.

We are, of course, aware that much of the beauty and, consequently, the growing popularity of such pictures depend on the skill and judgment with which the apparently absolutely necessary “retouching" and "touching-up" is done; but there can be no doubt that, judging from the specimens so frequently met with in photographic saloons, on the walls of our exhibitions, and in private collections, works of a high class, in this direction, is the rule rather than the exception.

[4] In submitting his 1866 application for a renewal of his original patent, Woodward described the artistic applications of the instrument: The object of my invention is, first, to furnish the artist or draftsman with an instrument by which he may be enabled to produce an accurate image of the object to be delineated by photography, and that will afterward portray on his canvas or other material an infallible representation thereof in light and shade, whereby a most accurate likeness or copy of any desired size may be produced, requiring only one sitting of the subject; and, secondly, to enable the photographic artist to print a picture on prepared paper, canvas, or other material of greater or less dimensions than those of the negative ordinarily used for such purpose, whereby he is enabled to use a more perfect negative produced by bringing the entire field of his picture within the focus of his instrument, and afterward throwing it up and printing it by concentrating the rays of light through the negative in the instrument and focusing the object on the prepared paper or canvas, instead of printing by superposition in the usual way.

Solar camera enlargements were newsworthy, reported in 1862 as "a most important and interesting application of science to the photographic art,"[12] and contemporaneous discussions of them make it apparent that they were compared in aesthetic terms to painting and drawing.

An enlarged full-length group of two young ladies in walking dress is the most satisfactory; the pose is easy and graceful, the drapery clear and distinctly rendered and full of halftone, and the whole give evidence of careful study.

[26] In the United States in particular the life-size 'crayon portrait' – a hand-coloured solar camera or later, a magic lantern, enlargement – remained popular into the early 20th century,[27] created using techniques described by Jerome A. Barhydt[28] and other contemporary practitioners.

Advertisements in the British newspapers in the 1880s for second-hand solar cameras proliferated as professional photographers started to abandon the device,[30][31][32][33][34][35] and by 1890, artificial light sources – gas, petroleum, limelight, magnesium and electric light bulb – sufficiently powerful to expose materials which were being made increasingly sensitive, were commonly used in enlargers,[36] so when, that year, Josef Maria Eder installed a Wothly solar camera on the roof of Vienna's Höhere Graphische Bundes-Lehr- und Versuchsanstalt the students would have considered it a vintage curiosity.