DiscolourationChanges of hue or value, often related to a single colour or pigment and frequently found over a whole painting or having uneven distribution (such as a difference between what has been hidden by a frame and what has been exposed to light). It is detrimental to the prevailing tone relations of the artwork and is often caused by aging.
LiteratureSpring M., Higgit C., Saunders D., Investigation of pigment-medium processes in oil paint containing degraded smalt, 2005, in: National Gallery Technical Bulletin, vol 26, London, pp 311-327
Kirchner E., van der Lans I., Ligterink F., Geldof M., Megens L., Meedendorp T., Pils K., Hendriks E., Digitally reconstructing Van Gogh's Field with Irises near Arles part 3: Determining the original colors, 2017, in: Colour Research and Application, vol 43. issue 3, pp 60-77
Roy A., Hendriks E., Van Gogh’s Sunflowers in London and Amsterdam, 2016, in: National Gallery Technical Bulletin, vol. 37, 2016, pp 2600-2610
Rioux J.-P., The Discoloration of Pinks and Purples in Van Gogh’s Paintings from Auvers, 1999, in: Cezanne to Van Gogh: The Collection of Doctor Gachet, New York, NY: Metropolitan Museum of Art, Harry N. Abrams, pp 104-114
Kubik M.E., Preserving the painted image: the art and science of Conservation., 2010, in: Colour: Design and Creativity vol.5 (2010) issue 5., pp 1-8