About this term
Source: Oxford University Press
Light-tight box with a small hole in one side, sometimes fitted with a lens, through which light from a well-lit scene or object enters to form an inverted image on a screen placed opposite the hole . A mirror then reflects the image, right way up, on to a drawing surface where its outlines can be traced. The camera obscura was the direct precursor of the modern camera, and its use by earlier artists can be compared to that made of the camera by artists of the 19th and 20th centuries. Moreover, a camera obscura was the device used by Thomas Wedgwood and Humphry Davy in the late 18th century in their attempts to project an image on to paper and leather coated with a silver nitrate solution; the image was finally fixed by Nicéphore Niépce in 1826–7.
The origins of the camera obscura go back at least to Aristotle, who noted the principle on which it works in his Problems. This was also noted by the Arabian philosopher Ibn al-Haytham (Alhazen; c. 965–1039) who recommended it to astronomers as a means of observing eclipses safely; it was frequently used for this purpose, often in conjunction with an astronomer’s reticle. This appears to have been its main use at least until the 16th century, though the English scholar Roger Bacon (1214–94) appears to have known of the mirror device by which the camera obscura was of interest and value to artists. Giorgio Vasari mentions an invention of Leon Battista Alberti that sounds as if it may have been a camera obscura, but it was not until the publication of the Neapolitan physician Giovan Battista della Porta’s Magia Naturalis (Naples, 1558) that the camera obscura became popularized as a mechanical aid to drawing, and not until the early 1600s that Johann Kepler gave it the name by which it is now known.
Following this the camera obscura became increasingly popular and important. Both Johannes Torrentius and Johannes Vermeer are known to have used it (the former thus laying himself open to a charge of witchcraft); so, notably, did Canaletto, who had a camera obscura made by the Venetian optical-instrument maker Domenico Selva. Among other painters who enthusiastically adopted it were Francesco Guardi, Michele Giovanni Marieschi, Luca Carlevaris and Sir Joshua Reynolds. John Harris mentions the camera obscura in his Lexicon Technicum (London, 1704) as being on sale in London; indeed, throughout the 18th century their use became a craze. They were enjoyed equally for the views they made possible, particularly the chiaroscuro effects produced by looking from or through a darkened area at a well-lit subject (perhaps similar to those created by the Claude glass and satisfying a similar 18th-century taste). Horace Walpole and Goethe are among those known to have owned and used a camera obscura, presumably for this reason. In 1747 the London instrument maker John Cuff published an anonymous contemporary poem praising the camera obscura, which gives some indication of the healthy market there was for these instruments. It contains much fulsome praise:Say, rare Machine, who taught thee to design? And mimick Nature with such Skill divine … Exterior objects painting on the scroll True as the Eye presents ’em to the Soul….
The camera obscura came in many sizes, some large enough, though portable, to warrant being covered with a tent; these could easily accommodate a man standing (and drawing) inside. Others, like sedan-chairs, were fitted with bellows, which the artist or viewer worked with his feet to improve ventilation. Sir Joshua Reynolds owned one (London, Sci. Mus.) that, with great ingenuity, collapsed down to the size and appearance of a book and could be stored as such.
From Grove Art Online