" High Contrast Pictures"
  Arie Van Praag MFIAP, ....Hon.ES-OGPh  

  High Contrast Pictures  
A photographic technique that is almost forgotten nowadays. It uses lythographic film and special developer chemical that render only black or transparent patterns, without grey tones. The amount of blackening is determined by the exposure time under the enlarger enabling variations or tone separation combinations. Pictures were made between 1970 and 1990.