Topic summary
Orthochromatic
Extracted from the Wikipedia article Orthochromasia.
Orthochromatic photography
Orthochromatic photography refers to a photographic emulsion that is sensitive to blue and green light but not red light. This type of emulsion was a significant advancement in early photography, as it allowed for the production of images with more accurate tonal reproduction than the earlier emulsions that were sensitive only to blue (and ultraviolet) light, e.g., the wet plate collodion emulsions.