Digital color restoration of old paintings

Abstract

Physical and chemical changes can degrade the visual color appearance of old paintings. Five digital color restoration techniques, which can be used to simulate the original appearance of paintings, are presented. Although a small number of color samples is employed in the restoration procedure, simulation results indicate that good restoration quality can be attained.

Automated colour grading using colour distribution transfer

“…In digital restoration [12] for instance, the idea is to recolour paintings that have been faded by smoke or dust. The process can also be used for colour image equalisation for scientific data visualisation [13] or simply useful for non-realistic rendering.…”

Experimental study on merits of virtual cleaning of paintings with aged varnish

“…The virtual removal of the discolored varnish on Leonardo's "Mona Lisa" was attempted [1] and other types of degradation were tackled, such as the craquelure [2] and fading of the eosin dye (geranium lake) [3] that affects many of Van Gogh's paintings. Early studies on virtual restoration [4][5][6] were working with tri-dimensional color spaces. Unfortunately, the color accuracy of trichromatic cameras has limitations, which are a consequence of the differences in the spectral response of cameras compared to the human visual system (i.e.…”

N-dimensional probability density function transfer and its application to color transfer

“…In the transfer of colour between two images, it is known as exampled-based colour transfer [14]. In digital restoration [12] the idea is to recolour paintings that have been faded by smoke, dust etc. If the target pdf is uniform, the process can also be used for colour image equalisation for scientific data visualisation [13] or simply used for nonrealistic rendering.…”