For centuries printmakers have experimented with a wide variety of techniques to create tonal effects in prints. Aquatint, an etching technique developed in the late 18th century, introduces a porous ground to the printing plate through the application of resin that is fused to the plate before it is etched in the acid bath. The inked porous ground produces an effect akin to wash or watercolor, which artists have exploited to dramatic, evocative ends. The show features a range of works, from innovative early examples of the technique by Francisco Goya and Jean-Baptiste Le Prince to haunting, spectacular images from the 20th century by Otto Dix and Pablo Picasso.