The purpose of this 1994 workshop was to introduce participants to traditional and modern varnishes and to compare their characteristics and handling properties. Twelve test panels from the workshop were brought to the Centre de Conservation du Québec (CCQ) in Quebec City and mounted on a wall in the paintings lab, where they were left to age for fifteen years. Visual comparisons were made to evaluate differences in colour change and gloss. It was concluded that adding Tinuvin 292 to mastic and dammar varnishes to inhibit premature yellowing (in the absence of UV light) is very important since all unstabilized varnishes made with these resins discoloured to some degree. Most proprietary varnishes showed no discoloration. However, those based on ketone resins gave less consistent results. It was particularly encouraging to see how well the Regalrez 1094 samples have aged. Their superior performance with regard to yellowing (with or without the addition of Tinuvin 292) and their rapid solubility in isooctane after 15 years of natural ageing may make Regalrez a suitable varnish for acrylic paintings. Surprisingly, four different unstabilized varnishes based on copal-oil formulations show only a trace of discoloration. It remains to be determined how these varnishes would age in environments where UV light is not filtered.