Madder lake is reported in the literature to have a characteristic pinkish-orange UV fluorescence, both in microscopy cross-sections imaging [1] and UV Fluorescence Photography [4]. Madder lake is the only historical red lake known for showing UV fluorescence. So, its UV fluorescence allows its identification. Though, I never could observe any UV fluorescence in my madder
Gouache, from the Italian guazzo, is a method of painting with opaque colors ground in water and thickened with gum and honey. The Head of Conservation at The Bergen Museum of Art, MSc. Yngve Magnusson, was so kind to send me over a Winsor and Newton Color Chart of Designer’s Gouache to be tested by Technical
I’m sharing in this post the Technical Photography images of my Historical Pigments swatches collection painted with gum arabic. I used a Nikon D800 36 MP modified for UV-VIS-IR and the set of filters for multispectral imaging described here. All the images are shot RAW and then edited in Camera RAW. VIS (Visible). Be sure