ABSTRACT
Traditional black and white film emulsions all differ slightly in the way they respond to different portions of the visual spectrum. This is partly what gives the emulsion films their signature qualities. In a way, the film also uses standard formulas for converting color to black and white, and that these too are like rigid grayscale conversions. One may also be familiar with the concept of using strong colored filters over the lens when shooting with black and white film and how this technique can be used to emphasize the contrast between certain colors, such as the use of the yellow, orange or red filters to add more contrast to a sky. The same principles apply to the way to use the Black & White adjustment to mix the channels to produce different kinds of black and white conversions.
