Basic Color Filters
Used to alter the color wavelength of light.

Filter No.          Description/Use
2A                      Pale yellow. Absorbs ultraviolet radiation.
2B                      Pale yellow. Absorbs ultraviolet radiation, slightly less than No. 2A.
2E                      Pale yellow. Absorbs more ultraviolet radiation than No. 2A.
8                         Yellow. Transmits less blue than No. 3.
11                      Yellowish-green. Corrects panchromatic film rendition to match tungsten impression of scene.
12                      Deep yellow. Minus blue filter (see No. 32 for minus-green and No. 44A for minus-red).
15                      Deep yellow. Darkens sky in landscape photography.
16                      Yellow-orange. Greater over-correction of sky than No. 15.
22                      Deep orange. Contrast filter, greater effect than No. 21.
24                      Red.
25                      Red tricolor. Color separation work, tricolor printing, and infrared photography.
29                      Red. Color separation with Nos. 47 and 61 and tricolor printing work.
47                      Blue tricolor. Color separation work with Nos. 29 and 61.
58                      Green tricolor. Color separation and tricolor printing.
90                      Dark grayish amber.
99                      Green. Equivalent to No. 61 plus No. 16 filter.