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     ABOUT MULTISPECTRAL DIGITIZATION & LUMIERE TECHNOLOGY

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The CNRS, Paris 6 University

Le Louvre Museum 
French Museums Researches & Restauration lab., Paris

The National Gallery, London

ICOM 2005

ARCHIVES 2006

CGIV 2006

CRISATEL PROJECT, IST

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du CNRS  & de  l'UNIVERSITE DE PARIS VI

Multispectral camera and radiative transfer equation used to depict Leonardo's sfumato in Mona Lisa

Mady Elias and Pascal Cotte Applied Optics, Vol. 47, Issue 12, pp. 2146-2154

Abstract

The technique used by Leonardo da Vinci to paint flesh tints--the sfumato--has never been scientifically depicted until now. From 100,000,000 reflectance spectra recorded on Mona Lisa, a virtual removal of the varnish is first obtained. A unique umber pigment is then identified in the upper layer and an exceptional maximum of the color saturation is underlined, both characteristics of a glaze technique. The modeling calling upon the radiative transfer equation confirms this maximum of saturation, the identification of an umber in the upper layer, and moreover underlines a mixture of 1% vermilion and 99% lead white in the base layer. Finally, the modeling, using the auxiliary function method, explains the spectacular maximum of saturation by the multiple scattering.

© 2008 Optical Society of America  

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Keywords (OCIS):
(030.5620) Coherence and statistical optics : Radiative transfer
(290.4210) Scattering : Multiple scattering
(300.6550) Spectroscopy : Spectroscopy, visible
(330.1690) Vision, color, and visual optics : Color
(110.4234) Imaging systems : Multispectral and hyperspectral imaging

History
Original Manuscript: January 8, 2008
Manuscript Accepted: March 14, 2008
Revised Manuscript: March 13, 2008
Published: April 18, 2008

Citation
M. Elias and P. Cotte, "Multispectral camera and radiative transfer equation used to depict Leonardo's sfumato in Mona Lisa," Appl. Opt. 47, 2146-2154 (2008)
http://www.opticsinfobase.org/abstract.cfm?URI=ao-47-12-2146

Abstract

Applying the cutting-edge forensic techniques of television’s CSI to the world’s most famous painting yields a fresh look at an old friend in Mona Lisa. A step-by-step examination of how Leonardo’s masterwork was constructed, using the latest advances in scientific observation, measurement, and analysis, this book almost literally peels back the layers on one of the most iconic images in world history. How did Leonardo prepare his panel, mix his paints, and compose his picture? For the first time ever a team of experts looks at these questions with an exacting scientific eye. Their answers shed light on both the mind of Leonardo and the wider world of Renaissance painting.

A fascinating combination of science, forensics, and art history, this gorgeous, oversized volume outdoes even the most imaginative novelist in cracking da Vinci’s creative code.

A New Multispectral Imaging System for Examining Paintings

Haida Liang,* David Saunders and John Cupitt

Scientific Department, The National Gallery, London , UNITED KINGDOM

Abstract

A new multispectral system developed at the National Gallery is presented. The system is capable of measuring the spectral reflectance per pixel of a painting. These spectra are found to be almost as accurate as those recorded with a spectrophotometer;there is no need for any spectral reconstruction apart from a simple cubic interpolation between measured points. The procedure for recording spectra is described and the accuracy of the system is quantified. An example is presented of the use of the system to scan a painting of St. Mary Magdalene by Crivelli. The multispectral data are used in an attempt to identify some of the pigments found in the painting by comparison with a library of spectra obtained from reference pigments using the same system.In addition, it is shown that the multispectral data can be used to render a color image of the original under a chosen illuminant and that interband comparison can help to elucidate features of the painting, such as retouchings and underdrawing, that are not visible in trichromatic images.

Journal of Imaging Science and Technology 49: 551–562 (2005)

Calibration and SpectralReconstruction for CRISATEL: An Art Painting Multispectral Acquisition System

Alejandro Ribés and Francis Schmitt
Ecole Nationale Supérieure des Télécommunications, Paris, FRANCE

Ruven Pillay and Christian Lahanier
Centre de Recherche et de Restauration des Musées de France, Paris, FRANCE

Abstract

The CRISATEL multispectral acquisition system is dedicated to the digital archiving of fine art paintings. It is composed of a dynamic lighting system and of a high resolution camera equipped with a CCD linear array, 13 interference filters and several built-in electronically controlled mechanisms. A custom calibration procedure has been designed and implemented. It allows us to select the parameters to be used for the raw image acquisition and to collect experimental data, which will be used in the post processing stage to correct the obtained multispectral images. Various techniques have been tested and compared in order to reconstruct the spectral reflectancecurve of the painting surface imaged in each pixel. Realistic color rendering under any illuminant can then be obtained from this spectral reconstruction. The results obtained with the CRISATEL acquisition system and the associated multispectral image processing are shown on two art painting examples.

Journal of Imaging Science and Technology 49: 563–573 (2005)

Two-dimensional multi-spectral digitization and three-dimensional modelling of easel paintings
Christian Lahanier*, Geneviève Aitken and Ruven Pillay

Centre de recherche et de restauration des musées de France

Palais du Louvre

Abstract

This paper presents the usefulness and utility of three complementary digitization techniques for the dynamic rendering of colour, roughness and shape of easel paintings. Twodimensional multi-spectral digitization and three-dimensional (3D) modelling of paintings are used for colour accuracy rendering and measurement, colour characterization, pigment identification, for high-definition visualization of the painting, and for the measurement of the shape of the support and the paint-layer roughness.

The experimentation was performed on several paintings. The results show the advantages of each technique.

Several viewers were developed to handle multi-spectral images and 3D models.

ICOM LA HAYE DEN HAAGEN - 2005

Spectral imaging of Leonardo Da Vinci’s Mona Lisa:
An authentic smile at 1523 dpi with additional infrared data
P.Cotte, D.Dupraz

Archiving 2006 Ottawa, Canada

Abstract

Two photos of the famous Mona Lisa were taken in October 2004 to contribute towards improving the technical and scientific data of the masterpiece before moving it in April 2005. The capabilities of the multispectral system developed by the LUMIERE TECHNOLOGY Company within the scope of the European CRISATEL project have made it possible to achieve optimal spatial resolution on the masterpiece, the highest level of sharpness ever achieved in the field of infrared reflectography, and a level of accuracy regarding color information which cannot be achieved with traditional technologies. From ultraviolet to infrared, all the details enhance the intimacy of this masterpiece. The scientific utilization of this data will undoubtedly be a major breakthrough to achieve better knowledge of Leonard De Vinci’s work. The remarkable nature of this masterpiece and its specific physical features have required appropriate parameterizations and preliminary tests which are described in this publication.

Download Pascal Cotte Conference at Archiving 2006 doc.PDF, 10,6 Mb

Spectral imaging of Leonardo Da Vinci’s Mona Lisa: A true color smile without the influence of aged varnish
P.Cotte, D.Dupraz
CGIV 2006 London, UK

AbstracT

Two photos of the famous Mona Lisa were taken in October 2004 to contribute towards improving the technical and scientific data of the masterpiece before moving it in April 2005.

The capabilities of the multispectral system developed by the LUMIERE TECHNOLOGY Company within the scope of the European CRISATEL project have made it possible to achieve optimal spatial resolution on the masterpiece, the highest level of sharpness ever achieved in the field of infrared reflectography, and a level of accuracy regarding color information which cannot be achieved with traditional technologies. Based on this new data, we suggest in this publication that the influence of aged varnish be removed, the significant discoloration of which alters the readability of the masterpiece

Download Pascal Cotte Poster JPEG

BIRTH OF A NEW  ERA FOR HIGH FIDELITY REPRODUCTION USING MULTISPECTRAL IMAGE ACQUISITION
Pascal COTTE,

Paris France October 2003

Multispectral Analysis and Spectral Reflectance Reconstruction of Art Paintings

Alejandro Ribés Cortés

Ph.D. Thesis

A dissertation submitted in partial fulfillment of the degree of “Docteur de l’Ecole Nationale Supérieure des Télécommunications“

Defended on 16 december 2003, Paris, France

Chapter 6. The CRISATEL Acquisition System.

A high-resolution multispectral color imaging system has been developed for the European

project CRISATEL. This system includes a multispectral camera and a dedicated high power

lighting system, both developed by LUMIERE TECHNOLOGY, Paris, France. In this chapter

we present and characterize the hardware of the CRISATEL camera. Afterwards, we evaluate

this acquisition system and using the data obtained on the evaluation we propose and

implement a calibration procedure. Finally, a correction system for the calibrated images is

described.

This is an experimental chapter where an actual multispectral acquisition system is studied.

We have designed and implemented software intimately related to the acquisition system: the

calibration and correction systems. These systems aim to acquire images that have not only

high visual quality but also a radiometrically controlled signal.