Zusammensetzung und Aufbau des berühmten Stradivari‐Lackes

Rediscovering Ducos du Hauron's Color Photography through a Review of His Three‐Color Printing Processes and Synchrotron Microanalysis of His Prints

“…This color print indeed dates from 1879. Microanalysis of the red pigment by confocal Raman spectroscopy demonstrates the presence of an organic dye of the anthraquinone family . Spectra of lake pigment references (organic molecules fixed to a mineral substrate, usually alum) of madder lake (mainly alizarin and purpurin) and carmine lake (cochineal lake based on carminic acid) show that the closest match corresponds to the carminic acid based lake in agreement with the 1878 recipes (Figure C).…”

Red lakes from Leonardo's Last Supper and other Old Master Paintings: Micro-Raman spectroscopy of anthraquinone pigments in paint cross-sections

“…the Body of Saint Mark, Pinacoteca di Brera, Milan. From top to bottom: a varnish layer [7], a blue layer containing ultramarine and smalt [6], a layer containing lead white and ochre pigments [5], a 40 μm thick pink layer containing red lake particles (smaller than 5 μm in diameter) mixed with lead white [4], a thin layer containing lead white and ochre particles [3], and finally a layer containing red lead [2] over a ground [1].…”

“…Madder [2,3] , from rubia tinctorum, or other kinds of rubia, is a mixture of purpurin and alizarin [4] , while Brazilein [5] , from Brazilwood, is particularly light sensitive. Laccaic acids [6] account for the dye produced by the lac beetle "Kerria lacca Kerr".…”

In Situ Infrared and UV–Vis Ellipsometries to Probe The Varnish Ageing and Swelling of G. Bellini “Transfiguration”

“…Varnishes are optically transparent layers applied to the surface of a painting, to make it "bright, beautiful and completely lasting", [1] according to the monk Theophilus, already in the 12th century, DOI: 10.1002/admi.202300563 describing their two main purposes. [2][3][4][5][6] First, varnishes modify the appearance of the painting by acting on the saturation of the colors and the gloss. Second, they are used to protect the surface and represent a physical barrier between the paint layers and the environment, preventing them from mechanical damage or UV-induced photochemical reactions.…”

“…Research aimed at preserving the protection afforded by varnish layers and the assessment of risks under storage conditions and during cleaning procedures is crucial to the field. [3] However, since the pioneering work of Stolow in 1954 [7] and later of A. Phenix (in the 2000s) [8] many technical and theoretical drawbacks ("the fact that there is no (analytical) technique capable of measuring the action of solvents under realistic processing conditions", according to Baij et al) [6] have prevented the community from making progress in understanding the action of solvents on oil paints and varnishes. Fife et al [9] used NMR Mouse to probe the action of solvent cleaning directly on historical paintings, but with limited time and depth resolution, which prevents from in situ monitoring in thin layers.…”