Camera lucida in brass with weighted clamp 3-part telescopic stand and adjustable prism and sight with tinted dark glass (c.1850).
The term ‘camera lucida‘ means ‘light room’ or ‘light chamber’. The camera lucida does not require a dark space to use as would be the case with a camera obscura.
Used to assist in drawing outline sketches of distant objects in true perspective.
With this instrument there is no projected image as it is based on rather different optical principles from the camera obscura. The optical parts of a camera lucida comprise a prism, mirror and lens that allow the user to see – at the same time – the image they are viewing superimposed over (but not projected upon) and the paper they are drawing on.
The user looks through the prism and can trace the image. However, this is not as simple as it sounds because as the user’s eye moves the superimposed image and the tracing will not be synchronised. This particular camera lucida has an extendable arm and a clamp. In this way it can be secured in position at one side of a drawing board or sketch pad with the prism set at a convenient height for use. The extendable arm is graduated on a non-uniform scale with positions 2, 3, 4, 5, 7, 10 and D.
The British artist David Hockney believes that many old master painters may have used a camera lucida to assist them in sketching outlines. He is of the opinion that Van Eyck and Caravaggio (amongst others) might have used a camera lucida because some changes in painting style coincided with developments in the science of optics.