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CAUTIONS TO READERS. “He warns the painter and glass-worker of the particular danger of flame when preparing varnish or blowing glass, he tells the gilder of the difficulty of recovering his gold leaf if he should lose it in a draft, he cautions the workman about the dangers of using quicksilver on an empty stomach.” (The last caution sends shivers down my spine -- handling raw mercury with abandon). https://lnkd.in/d7yzXt5 View in LinkedIn

SO ENDS this first of two weekends on the twelfth century text on how to do crafts by Theophilus. Even today, there are gems in this work for those interested in the crafts. Above all, it is an insight into the depth of knowledge of these people and the amount of skill needed to do their work. Never again visit a museum and see a painting, a piece of glasswork, or metal work from this period or before, and forget the true depth behind each one. View in LinkedIn

INTIMATE KNOW-HOW. “He knows, for example, all the actual problems of gilding: that too much glue will blacken the gold, that impure glue will cause it to crumble and too thick a leaf will not stay on.” https://lnkd.in/d7yzXt5 View in LinkedIn

MODERN FLAKE-WHITE. “A traditional lead based white, it is steeped in painting history. Evidence for its use can be found in all the oldest civilisations: as a cosmetic in 400BC Athens, by the Ancient Egyptians and back to the earliest Chinese paintings. Considered one of the earliest pigments, it is basic lead carbonate with zinc oxide and was the only widely available white pigment for artists until the emergence of others in the 19th century.” https://lnkd.in/d3iMu_c View in LinkedIn

THEOPHILUS WAS A CRAFTSMAN. “He mentions that he has gained experience of the methods that he is about to describe, having “examined them individually with careful trial and proved them all with hand and eye.” https://lnkd.in/d7yzXt5 View in LinkedIn

MAKING FLAKE-WHITE. “Get some sheets of lead beaten out thin, place then to dry, in a hollow piece of wood, and pour in some warm vinegar or urine to cover them. Then, after a month, take off the cover, and remove whatever white there is.” (Lead oxide), https://lnkd.in/d7yzXt5 View in LinkedIn

IMPLICIT CHEMISTRY. In the middle ages, chemistry as such did not exist, but it was ingeniously practiced empirically by craftsmen. It is rather easy, today, to read his recipes and deduce the chemical reactions that were being undertaken. Like the ingenuity of cooking methods worldwide, artisanal workers came upon extraordinary solutions to their undertakings. I call it the distributed genius spread over generations of trial and error. https://lnkd.in/d7yzXt5 View in LinkedIn

MAKING SALT GREEN. “Next, gather some twigs, place them in the hollow box so that two parts of the cavity are below and one part above, coat the copper sheets on each side with pure honey over which you sprinkle pounded salt...pour warm vinegar or hot urine until a third part of it is filled. You should place this wooden container in a place where you can cover it on every side with dung. After four weeks take off the cover and whatever you find on the copper scrape off and keep.” (ie: approximately sodium chloride plus copper in acid makes copper chloride CuCl2). https://lnkd.in/d7yzXt5 View in LinkedIn