First President of Britain’s Royal Academy of Arts and eminent theorist of Augustan aesthetics, Joshua Reynolds was an inveterate chemical experimenter. Using a secretive laboratory of varnishes, waxes, and fugitive pigments, Reynolds crafted visually striking images that came together quickly and stopped his audiences dead in their tracks. Yet, as generations of horrified conservators have discovered, those images soon began to deteriorate as objects—flaking, discoloring, visibly altering in time. Portrayed by Reynolds in youth, many aristocratic sitters returned home after dissolute adventures on the Continental Grand Tour to find (in the words of one period biographer) “that the portrait and the original had faded together and corresponded, perhaps, as well as when first painted.” If an abundance of apparently anti-alchemical sentiments can be found in Reynolds’s intellectual circles—from the Scottish Enlightenment promoters of “philosophical chemistry” that influenced him to the scathing, conservative criticism of chemists’ destabilizing political force voiced by his close friend Edmund Burke—this paper offered a broader view. Placing Reynolds within a particularly dynamic moment in the history of chemistry and a longer tradition of chemical image-making in the circles of the Royal Society of London (Britain’s leading key scientific institution of which Reynolds was a member), Mathew Hunter's research explored the larger problematic of making and thinking with temporally-evolving chemical images in the later eighteenth century.