Colour Today
This image shows the Mona Lisa as she appears in the Louvre, in Paris, today. There is a sweetness to the soft light that falls upon her from the top left of the painting, and her delicate hands and the subtle veil on her head also contribute to this effect. One of her most striking features is her eyes, which seem to follow you as you move from left to right, yet do not gaze directly at you. The effect can be a little disconcerting, and has sparked much discussion over the years.
The landscape behind the young lady comprises three horizontal sections. At the level of her chest we see the 'man-made' section: a road on the right, and a river and bridge on the left. At the level of her neck the landscape becomes 'harder', with a deep lake and forest. Finally, towards the top of the painting we see the landscape become even harsher, with rocky mountains disappearing into the fog.
It has been said that the sky could represent God. Indeed, many believe that the landscape is much more than a background, having deep philosophical undertones.
Image of Genuine Colour
Pascal Cotte's multispectral camera has allowed us to accurately identify the pigments used in the Mona Lisa, allowing us to finally see her as Leonardo da Vinci intended. By recreating each of these pigments as they would have originally appeared, it was possible to generate a replica of the Mona Lisa that shows exactly how she looked when she had just been painted.
Pigment analysis has shown that the pigment used to paint the sky is composed of a deep blue gemstone called lapis lazuli mixed with white lead. The skin is painted with the powder of mercuric sulfide ore, known as vermilion, mixed with yellow lead and white lead. The paint used for the sleeves also contained white lead and yellow lead.
It is interesting to note that Leonardo has depicted the mountains in blue. This may seem strange at first, but in fact, mountains are depicted in blue in all of Leonardo's paintings, including the Virgin of the Rocks. In his Treatise on Painting, Leonardo wrote, "You know that in an atmosphere of uniform density the most distant things seen through it, such as the mountains, in consequence of the great quantity of atmosphere which is between your eye and them, will appear blue."Varnish Removed
Pascal Cotte's multispectral camera gives us the unique ability to 'virtually' remove the influence of varnish.
Physical removal of the varnish is impossible without damaging the previous artwork, as the varnish is now mixed with the underlying pigments to the point where one could not be removed without the other.
This simulation therefore offers a unique opportunity to look a little closer at art's most mysterious character. Without the influence of the varnish on our perception of the painting, we are able to see details that were previously invisible.
See for yourself: the sleeves show more gold; the sky is a more vibrant blue; clouds are clearer; and the landscape takes on a different tone.
False Colour Infrared
Here we dig deeper still into the layers that underlie the Mona Lisa we know.
The optical properties of infrared light allow it to penetrate beyond the visible surface layer of a painting to reveal underlying details that would otherwise have remained invisible. Infrared light is not visible to the human eye, but we can simulate it with visible light wavelengths using scientific data obtained from the multispectral camera.
Here we see a virtual image representing the results of Cotte's infrared scan.
As you look at this image, you are effectively viewing it as if your eyes had the superhuman ability to detect infrared light. The first thing you'll notice is that the colour spectrum of the painting has completely changed towards reds and oranges. But this 'false colour' is only one effect of the infrared light. It also allows you to see beyond the visible surface layer. Hidden beneath the surface are details of retouching and restorations, and underlying drawings and pigments. These details represent the 'secrets' that Pascal Cotte was able to identify and analyse to give us a much deeper understanding of a complex and mysterious artwork.
Reverse False Colour Infrared
When Pascal Cotte converted the infrared image of the Mona Lisa into images with visible colours, he was able to create multiple images using different parts of the visible light spectrum.
In this image, Cotte has converted the infrared information into shades of blue, rather than reds and oranges as in the previous image. This provides greater detail in the deep, dark areas of the painting.
No specific discoveries came from the image, but it formed one more aspect of a thorough, detailed investigation, helping to consolidate and build upon the 25 'secrets' Pascal Cotte was ultimately able to compile.