Chapter 6
Eye sensitivity to colours Measurements carried out on the spectral sensitivity of single cells supply a physiological basis to explain the characteristics of the visual perception. The response of the eye to different coloured stimuli varies according to the colour as the human eye assesses in different ways the intensity corresponding to different wavelengths. However, this is a subjective phenomenon. To a yellow-green radiation (wavelength of about 555 – 560 nm) the eye responds with the highest sensitivity equal to 100%. The sensitivity to all the other lengths can be assessed in relation to this maximum sensitivity. With red radiations, or tending to infrared ray, the wavelengths are absorbed by the eye in a weaker way. The same accounts for the radiations next to ultraviolet where the wavelengths are absorbed by the cornea and the lens but do not reach the retina. The colour we attribute to a surface corresponds to the wavelengths of the light either reflected or diffused. This way, we can state that colour, shape and definition of the light/dark relationship are determined by our eyes’ processing of the light emitted by an object. One of the most interesting features of the colour vision is the subjectivity of each individual and from the above synthesis on the physiology of the human eye we can infer how complex our relationship with the colour perception may be and how subjective its detection is. Statistically it is yet possible to establish a general rule to define the colour which includes the majority of the population, leaving out pathological psychological or physiological deficiencies such as colour-blindness, achromatopsia and other visual diseases. The history of artworks reproduction Having learnt that the camera was built with the aim of reproducing the human eye and that the colour perception is subjective, now we can delve into the history of the reproduction of the works of art. Since the announcement of Daguerre’s invention the reproduction of the works of art has been considered as one of the fundamental subjects in photography. The two main qualities of the new invention, precision and clarity, have been praised even by its most stubborn detractors. For the first great photographers the reproduction of artworks represented a rather challenging and tough confrontation, above all as regards engraving.
As Henri Zerner has recently remembered, it was right on this ground that the future of art photography was mostly played. In that period, the faithful representation of a painting or drawing was the best chance for a photographer to show his skill to understand the spirit of the artist, grasp his style and reproduce it. In 1851 Francis Wey commented on the value of the paper photography in these words: “As the painter-copyist and the engraver may be competent and capable, inevitably they will end up changing the character of the model. Otherwise, they will not be able to copy it. Faced with these difficulties, we can only resort to the intervention of heliography and it is precisely in this field that this technique is called to produce wonders.“ (La Lumière, March 23, 1851) The technical limits of illumination, the difficulties in replicating the chromatic values of the canvas, the impossibility of moving the work for shooting purposes contributed to exalting the talent of the first art photographers even more. By the mid-nineteenth century there take hold the first trading attempts to spread the artworks by means of photography. In Lille, Louis Désiré Blanquart-Evrard starts up a printing press laboratory specialized in the printing of photographs where, on explicit request of the artists and art collectors, reproductions of architecture and artworks are made. Since 1853, the Goupil publishing company, specialized in the production and selling of hand engraving, has been selling various photographs among which those taken in Egypt by Félix Teynard. From 1853 to 1858, Goupil sells various series of works among which Notice sur la vie by MarcAntoine Raimondi illustrated by the photos of Benjamin Delessert, L’Oeuvre de Rembrandt with photos of the drawings made by the Bisson brothers and L’Oeuvre de Paul Delaroche, the first publication devoted to a contemporary artist, printed in 1858 with photos by Robert J. Bingham. In 1855, Adolphe Disdéri photographs the halls of the Universal Exposition of 1855. The editorial by the painter Edmond Lebel, recently bought by the Musée d’Orsay, includes a collection of pictures of the paintings exhibited during the exposition; HDR Photography - A Practical Guide
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