Lith
Lith Printing is an alternative darkroom technique, wherein silver gelatin black-and-white images undergo a process called infectious development. Highlights remain soft and bright, shadows become cold and hard, and the mid-tones grow grainy and warm in color. The color shift is rendered through the development process, not from post-printing toning, and can be quite variable.
For more information, visit British photographer Tim Rudman's website: worldoflithprinting.com