The material and technical research into the paintings of James Ensor is performed at the museum’s conservation workshop. In this series of articles, we also intend to familiarise the public with the research methods and techniques applied. In the present contribution, Adri Verburg elucidates false colour imaging, a research approach that combines various techniques.
James Ensor, Flowers and Vegetables (false colour image)
False-colour images are images that represent objects in other colours than the ‘true’ colours
perceived by the human eye and rendered in a regular colour photograph. They often consist in a
combination of images recorded in wavelengths that are invisible to the naked eye – such as X-rays,
ultraviolet and infrared - with images in the visible spectrum, such as ordinary colour
photographs. The physical properties of the object studied determine the choice of spectral bands.
Images recorded outside the visible spectrum are represented as greyscale images. However, these are often difficult to interpret, as the human eye is only able to distinguish up to sixteen different shades of grey. By modifying such images into false colour, the greyscale is converted into a colour palette better suited to our vision: as we are able to distinguish between millions of hues, much greater detail becomes visible.
James Ensor, Flowers and Vegetables (Detail false colour image)
An infrared false colour image or an IRR FC is an amalgamation of a regular image comprised of the three bands of the visible spectrum – red, green and blue – and an infrared image in the 950 to 1050 nm band. The latter is combined with the red and the green bands of the regular colour image; the blue spectral band is unused.
This technique yields an image that is easier to read than an infrared image. The relationship between the upper visible paint layer with the build-up of and alterations to the underlying (ordinarily invisible) layers becomes discernible. In the case of Ensor’s Flowers and Vegetables, for example, it becomes apparent that Ensor originally added a pitcher or a vase in the right background which he subsequently overpainted: a classic example of a pentimento. The approach also reveals that he originally signed the painting slightly higher up than the position of the present signature. In addition, colour shifts in the IRR FC provide information about the pigments used. Azurite is rendered as a dark blue, lapis lazuli as red, and red lacquer as orange.
James Ensor, Flowers and Vegetables, KMSKA
More about the painting
Flowers and Vegetables, 1896
Oil on canvas, 81.5 x 100.3, bottom right: ENSOR/ 1896, inv. no. 1959.
Ernest Rousseau Collection, Brussels; donated to KMSKA in 1921 by the following friends of the museum: Mrs Georges Born, Alphonse Aerts, Henri Fester, Charles Franck, François Franck, Louis Franck, Laurent Fierens, Charles Good, Théo Kreglinger, Ivan Maquinay, Enrique Mistler, Max Osterrieth and Maurice Speth.