Solarized Hellebore, photo by Harold Davis.

Solarization in photography reverses blacks and whites. Also called the Sabattier effect, in the chemical darkroom solarization was achieved by exposing an already exposed negative or print to light before development was finalized.

In the Photoshop darkroom, there are of course a number of ways to achieve a simulated solarization effect; the solarized (and converted to monochrome) version of Hellebore Curves is one example.