The contribution of the fluorescent tube is not limited to the spectacular aspect of the discoveries described above. Under this light there also appears a great quantity of information (Table 9.1), whereas with a UV lamp, photography with filters, special films and image manipulation, the data are gathered separately. These normal methods have in no way been replaced. However, the fluorescent tube enables one to make remarkable observations such as those below, with great visual comfort, in contrast to the Wood lamp which makes one's eyes tired very quickly:
• The concentration of red pigments can be evaluated as soon as the painting is lit.
• The paints and natural oxidations can easily be distinguished from each other.
• The rock support is differentiated from all the other elements stuck to its surface.
• Patinas can be seen and precisely determined.
• Surfaces of calcite can easily be localized where they were previously unknown.
• Algae and lichens are clearly delimited, while others which were unsuspected betray their presence.
• Bones and bone fragments which were unknown on the walls and floor have been revealed.
• Imperceptible fossils, enclosed in the rocky support, are indisputably located.
• Flints (identical) display their different aspects (colours, patina, breakages, etc.).
• Blows struck against the wall and surfaces that were destroyed in ancient times can be identified.
• Historical scratches can be recognized as such.
Table 9.1 Colours perceived on the walls of Gouy according to the lighting used
Without special lighting
By the light of the vegetal fluorescent tube
By black (ultraviolet) light (320 400 nm)
General colour: the white of the chalk, which is mixed with a whole range of greys, with no possibility of attribution
Dominant: purplish pink attenuated by a rapid adaptation of the eye (example: the white, although pinkish, is perceived as white)
Dominant: dark blue
Other colours: grey, light blue, purple blue, purple
PAINTING no. 1
Grey mixed in with all the other greys
Grey (among other greys)
Red (can be seen with the naked eye), identical to painting 5
Red (can be seen with the naked eye), identical to painting 4
Bone fragment Discernible with difficulty
Historical scratches Fossil Flint
Discernible with difficulty Grey, white
Grey (various, up to black) Grey (among other greys)
Dark red Red
Orangey red Intense red
Active concretion: white
Grey (among other greys)
Grey (among other greys) Barely perceptible grey Intensive luminescence saturated pink red
Dark grey found on all the walls Fluorescent white (luminous)
Dark yellow Shining white
Yellow (typical) White
Grey, blue, brown, Brown, black black, yellow
Very bright light green Grey (among other greys)
Was this article helpful?