At the National Gallery of Scotland this summer, an unusually proficient 2006 Festival Exhibition of the work of the late Renaissance painter, Adam Elsheimer (1578-1610), has just opened. The majority of the over 30 known paintings displayed are executed on copper, and to surmount usefully the drawback to the viewer of their diminutive size, each ticket purchased will also be accompanied by a loaned magnifying glass, the better to explore these brilliant miniaturist works. Capacity must inevitably be limited, however, to one magnifying glass per painting. There are further ramifications: this may be the first expansion of the audio-visual aid syndrome, which has caused road blocks in major exhibitions, such as the National Gallery's fine Raphael show last year. Or perhaps artists themselves will take control by offering aids. For Damien Hirst, a stepladder? And for the Chapman Brothers, a magnifying glass will surely do there.