Did the technology exist at the start of the Renaissance to produce optics of the necessary quality?
There is ample evidence that not only were suitable opticsboth refracting and reflectingavailable, but also that they were inexpensive. Tomaso da Modena’s 1352 paintings of ‘Hugh of Provence’ and ‘Cardinal Nicholas of Rouen’ show, respectively, spectacles and a magnifying glass, and ‘Isnardo of Vicenza’and ‘St. Jerome’ both show concave mirrors. From: Tomaso da Modena, Robert Gibbs (Cambridge University Press, 1989) and Tomaso da Modena, Luigi Coletti (Neri Pozza Editore, Venezia, 1963). About these mirrors, Robert Gibbs writes in his 1989 book on da Modena that “Isnardo da Vicenza is preparing his office; there is a reading glass (an enlarging-concave-mirror) on the shelf behind him.” Further, in a footnote to that sentence, Gibbs explains “Mirrors, despite their inconvenient habit of reversing the text, were used alongside lenses to enlarge small and faded handwriting.”(note: when properly oriented, concave mirrors magnify the text without reversing it). Gibbs continues in his footno
