Contrast Control Filter
From Nikonians Wiki - FAQs, Photo Glossary, Good Photo Locations, Help
Filters used in black and white photography to emphasize contrast in various degrees. There are six major types: Y (Yellow), Y/G (Yellow/Green), G (Green), O (Orange), R (Red) and the not so frequently used B (Blue), for portraits, to strengthen skin tones and bring out more detail in faces. Contrast filters improve the separation of tones. The deeper colored the filter the more pronounced the contrast effect.
