This deep orange filter darkens blue, violet, green and yellow-green. It particularly useful for all landscape and architectural photography(on black and white film) requiring vivid contours. The sky is distinctly toned with the clouds clearly contrasted against it. It is suitable for landscapes and nature scenes.
Lee gelatin filters are available in 3 x 3" (75 x 75mm), 4 x 4" (100 x 100mm)..
Filter factor is 4 (+2 stops)
Reviews LEE Filters 4x4" Light Red #23A Polyester Filter for Black & White Film