The Formatt 4 x 4" Yellow-Green 13 Filter is commonly used for a noticeable increase in contrast with black and white films.

The #13 yellow is a bit more contrasty than the #11. Contrast in black and white is generally controlled by yellow, orange and red filters with red producing the greatest contrast. Moderate changes can be accomplished with yellow which can, generally, bump up the contrast just enough to make the difference between a "muddy" print and an acceptable image.

• Enhances landscapes, marine scenes and aerial photography with more effect than a Yellow 11 filter
• Recommended as a basic filter for use with Kodak Aero Ektachrome Infrared film