Commonly used for a noticeable increase in contrast with black and white films. Especially useful for clear contrast between blue sky with clouds and foreground. It is also 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 2 (+1 stop)
Reviews LEE Filters 3x3" Deep Yellow #12 Polyester Filter for Black & White Film