Solar camera

The solar camera, or solar enlarger, is an ancestor of the darkroom enlarger, and was used in the mid-to-late 19th century to make photographic enlargements from negatives.

Other uses

Solar was a brand of conventional darkroom enlarger marketed post-WW2 in the United States by Burke & James Inc., Chicago.

Description

Early photographic materials were less light sensitive, and prints were made by simple contact ("contact prints"). The solar camera enlarger permitted photographers to make enlargements from glass negatives. However, exposures required for making such copies from negatives increase inversely with enlargement area. Photographers therefore employed the most powerful light source then available: the Sun.

Solar cameras were at first freestanding, a design based on picture-taking cameras but with the relative position of negative and lens reversed so that sunlight shone through the glass plate to be projected onto photo-sensitive paper or an emulsion on other substrates (glass, fabric, leather etc.) inside the instrument. Mounted on a stand, they could be rotated to continuously face the Sun.

Identifying characteristics

Prints usually required enhancement, and the results were often advertised as 'crayon portraits', the prints reworked with pastel crayons and varnished for protection. At first glance they resemble a photograph but closer inspection detects distinctive crayon strokes, mostly distinct in the hair and beard areas, and outlining the irises of the eyes, and coat lapels and other margins. They were common in the latter part of the nineteenth century and were often made to life-size. Others were prints on sensitised canvas that was overpainted in oils, so that they are harder to distinguish from paintings. Portrait painters who could not afford to own an expensive solar camera could mail negatives to photographers such as Albert Moore of Philadelphia to enlarge the negative onto paper or canvas. They would use the photograph as a starting point and could freely alter backgrounds, fabric, style and patterns of the clothing, and even the sitter's expression.

Inventors

A number of photographers, inventors and photographic businesses contributed to the design development of the solar camera.

A predecessor was the solar microscope, 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. Invented by T. Wedgwood, Esq. With Observations by H. Davy in the first issue of the Journals of the Royal Institution of Great Britain.

Baltimore painter David Acheson Woodward's 1857 solar enlarging camera was a large instrument operated out-of-doors that could produce life size prints from quarter plate and half plate negatives with an exposure of about forty-five minutes. He used sunlight and copying lenses for enlargements from a small negative onto large photographically sensitized paper or canvas, which he would then paint over in oils. 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.

Woodward's technique influenced others, including the American portrait painter Erastus Salisbury Field who completely overpainted the enlargements of portraits that he used. During Woodward's 1859 visit to England, Léon Cogniet also took up the technique. In the 1860s and 1870s advances on Woodward's 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. Jacob Wothly of Aachen improved Woodward's design with a reflector and presented it to 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.

M. Monckhoven's 1864 solar enlarger (engraving)

Désiré van Monckhoven's Belgian August 1863 patent for “an optical apparatus intended for enlarging by projection” was a modification of Woodward's design and had an appearance more like a modern horizontal enlarger. It corrected for spherical aberration (“appareil solar dialytique”) for sharper, more even light, for which he received a bronze medal at the Exposition Universelle (1867). After securing patents in England and France he went into manufacture. His apparatus was built into the darkroom wall, while J.F. Campbell's vertical design of the following year gathered light through an opening in the roof.

Nadar used Alphonse Liebert's enlarger for his first enlargements around that time, a design which used a hand-operated drive to keep the condenser lens focussed on the sun directly; with no mirrors, exposure times were decreased.

Louis Jules Duboscq's apparatus, like Quinet's, used electric light, and was shown to the Paris Photographic Society in 1861.

Demise

Advertisements in the British newspapers in the 1880s for second-hand solar cameras proliferated, 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, 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.

Even at the turn of the century simple folding daylight enlargers still found a use amongst amateurs to easily produce prints of a fixed size; one made by Griffin and Sons to enlarge quarter-plates to whole plate size, with achromatic lens built in, was 12s 6d (£60, or $US80 in 2020). Some cameras were made convertible to use in a similar manner.

See also

• Contact printer for a non-enlarging method of producing photographic prints;
• Image projector for a directory of projector types;
• Overhead projector for another use of a similar design, for display;
• Epidiascope for a design that could project images of opaque originals;
• Photographic printing for an overview of analogue photographic printmaking methods;
• Hockney-Falco thesis for discussion of earlier use of projected enlargement by artists.