Annual General Meeting
Notice is hereby given of the Annual General Meeting of the Colour Group (Great Britain). This will be held at the Oliver Thompson Lecture Theatre, Northampton Square, City University, London EC1 at 14.00 hrs - only members may vote.

Guest lecture

Prof Patrick Callet
Vice Chair Centre Français de la Couleur (CFC) Ecole des Mines (Paris) & Ecole Centrale (Paris)
Spectral Simulation for Cultural Heritage -- A scientific Methodology and Some Examples
An abstract is shown lower down this page.
The picture above comes from the project by Prof Callet and his students to determine the pigmentation of the once polychromatic sepulchre of Philippe Dagobert in "eternal repose" awaiting the resurrection in prayer (basilique de Saint-Denis, Paris, 13th century).
The picture below shows the tomb "as is" with only traces of colour.

ABSTRACT
We present successively three parts of a general working program on the physically based rendering of cultural heritage objects or monuments. We attempt to illustrate how it is possible to offer to our eyes some plausible restitutions of what might have been the visual appearance of an object many centuries ago.
The first section concerns general properties of the spectral and complex components of the dielectric tensor of homogeneous materials. It also describes some practical considerations on lighting and simulation. Then we apply, with examples given by ancient and more recent studies on bronzes, the metallic aspect. The first works on metallic reflection concerned silver-lead alloys used in Mesopotamia 22 centuries ago. That study was the effective foundation of what we now call Virtual Metallurgy.
The second section discusses some questions and models relative to the rendering of polychromy, gilts and natural lighting effects during the medieval period. Thanks to the simulation of a global illumination in spectral rendering operating with the photon mapping algorithm, a new interpretation of polychromy effects is proposed, including the lightguide effect produced by the gilts. Many measurements on formulated polychrome samples and spectrophotometric measurements concerning natural lighting at sunset were made to validate that new hypothesis.
The third section presents the project CALLISTO-SARI now in development and some questions relative to the virtual restitution of the church of Royaumont destroyed during the French Revolution.
All the previous projects have been included in a video film translated in many languages (Greek, Chinese, German, Spanish, Portuguese, Polish, English). The last video production Facsimile will be presented at the AGON international film festival of archaeology in Athens (May 8-13th).
Prof Callet hopes to bring samples of medieval artefacts to be examined.

Venue: Oliver Thompson Lecture Theatre, City University, Northampton Square, London

Admission: Free and open to all