The multispectral camera
The multispectral camera provides high resolution images. The definition (DPI) depends on the dimensions of the work to be digitized.
List of images produced :
- Definition : from 300 to 1500 DPI (Pixel per Inch)
- Image type : TIFF and JPG
- Resolution : 12000 x 20000 pixels
- Colors (standards) : CIE LAB D65 and RVB
- Color image, standard CIE LAB D65
- Color image, standard RVB
- False color infrared image
- Infrared image 800 nm
- Infrared image 900 nm
- Infrared image 1000 nm
- Gray tone image, measurement of light reflection « L »
- Gray tone image, distribution of color space « a »
- Gray tone image, distribution of color space « b »
Examples of images produced
L.A.M. imaging technique (Layer Amplification Method)The L.A.M. uses the 13 images of the MultiSpectral Camera.
In addition to high-resolution images, this technique generates 1650 images calculated with mathematical algorithms based on the laws of light / matter interaction.
These images make it possible to highlight underlying information that is invisible to the naked eye and sometimes invisible to Infrared.
It is the essential complement to traditional scientific imaging methods: X-ray, Infrared 1700/2500 nm, UV fluorescence etc.
This technique made it possible to discover new elements about the Mona Lisa :
See L.A.M. imaging videos:
- Video 1 Mona Lisa’s index finger pentimento
- Vidéo 2 Mona Lisa’s big hand
- Video 3 Mona Lisa’s hidden face
- Video 4 Mona Lisa’s two mouths
- Video 5 Mona Lisa’s forehead
L.A.M. example – 3 different states
Virtual paint removal
The spectra measured by the multispectral camera can be reprocessed to eliminate the influence of an old yellowed varnish.
A database of artificially aged varnishes allows an algorithm to simulate and calculate colors without the varnish. The result does not give the original colors but the colors underlying the varnish, which have deteriorated over time.
Mona Lisa paint removal
Identification of original pigments and colors
The spectra measured by the multispectral camera make it possible to identify certain pigments. It is a complement to traditional studies (XRF, Micro Raman, etc.). Software searches the pigment database for combinations of spectra that approximate the spectra measured on the board.
The identification of pigments is an essential contribution in the authentication protocol of an artwork.
Mona Lisa original colors
After doing the virtual paint removal and identifying the pigments, it becomes possible to find the original colors.
- P. Cotte, D. Dupraz « Spectral imaging of Leonardo Da Vinci’s Mona Lisa: A true color smile without the influence of aged varnish » in proceedings of IS&T CGIV’06, 311 – University of Leeds, UK, 2006
- P. Cotte, D. Dupraz « Spectral imaging of Leonardo Da Vinci’s Mona Lisa: An authentic smile at 1523 dpi with additional infrared data », in proceedings of IS&T Archiving’06, Ottawa, USA, 2006.