“My material is light,” says Helsinki School photographer Niko Luoma (born 1970), and “my process is a combination of ... calculation and chance.” Inspired by mathematics and geometry, and elaborating on the rich tradition begun by August Strindberg’s celestographs, Luoma creates elaborate and marvelously evocative photographic abstractions, in compositions of lines and geometric shapes. His methods are purely and emphatically analog: light-sensitive materials repeatedly exposed to light. The delicate crosshatched networks of lines in his series Symmetrium, for example, were built up through thousands of exposures on a single negative. Working thus, Luoma’s approach may said to be both accretive and chance-based, for the composition of the final image, as a collaboration with light itself, is wholly unpredictable. This volume compiles works from the past decade.