Erratum: Visual degradation in Leonardo da Vinci's iconic self-portrait: A nanoscale study

In our recent Letter, 1 it was originally stated that M.Livesey "closely read and occasionally corrected" the English manuscript. It transpires that this is not an accurate statement, and that in fact M. Livesey did not "closely read and occasionally correct" the original manuscript, for which reason his name has been removed from the Acknowledgements. Therefore, the last sentence "Finally, we thank M. Livesey for his close reading and occasional correction of our manuscript in the English language." must be deleted. Furthermore, we indicate two typos to be corrected: (1) Page 2, left column: "the reflectance that an infinitely thick paper sample would have, was ascertained, 11,12 for full explanation)." It should be: "the reflectance that an infinitely thick paper sample would have, was ascertained (see supplementary material 28 for full explanation)." (2) Page 4, left column: "for granting permission for the diagnostic study of Leonardo's da Vinci's self portrait." It should be: "for granting permission for the diagnostic study of Leonardo da Vinci's self portrait."