Hanne Darboven and Raphael Hefti, Camden Arts Centre - review

Early on in this show, she introduces the term "variations", and this is the key to unpicking her work. Darboven trained as a pianist and was drawn to the abstraction within music - in some calculations, numbers are turned into groups of lines not unlike staves. These drawings became musical scores, and one of the pieces they inspired plays in the show's final room. Suddenly all those scratchy sums coalesce into arpeggiating organ tones - an uplifting end to a dense but fascinating show.

By contrast, Raphael Hefti provides instant sensory delights. A series of photographs uses the powder formed from inflammable spores of the Lycopodium plant, which early photographers used to create flash. Hefti uses the powder to expose photosensitive paper, creating images resembling both fireworks and spores under a microscope. The installation Subtraction and Addition (2011) initially looks minimal, featuring thick and colourful pieces of glass propped around the room.

To create them, Hefti exploited accidents in the industrial process used to make the non-reflective glass which almost imperceptibly covers paintings in museums around the world.

Through pushing the production process to extremes, Hefti makes the glass anything but invisible - he creates abstract compositions on their surfaces, and places them to make maximum use of the light flooding the room, and to mirror the architecture of the gallery. The result is a beguiling play of filtered light, morphing colour and shifting reflection.

Both until March 18 (020 7472 5500, camdenartscentre.org)

Hanne Darboven and Raphael Hefti
Camden Arts Centre
Arkwright Road
NW3 6DG