The ULC ™ (Universal Light Code) is a trademark of Black Cat PhotoProducts, Inc. and is based on a new light code that forms a notation for natural, existing and available light. The ULC is a simple light code for photographic notation consisting of twenty six "file folders" that contain the full range of light that can be seen by the human eye. This interactive chart acts as a "decoder" and translates the scene into exposure settings.

The use of the Universal Light Code encourages the sharing of photographic exposure information. When the light code for a scene is given to another photographer, this chart is used to select their film speed (ISO), then any shutter speed or aperture (f-stop) combination shown as a "good exposure" may be used for their final exposure.

LIGHTCODE is a photo forum moderated by Jim Lehman, located here: Members may post their photos in the ULC folder, consisting of 26 A-Z sub-folders, where scenes are grouped by the amount of light in the scene (Scene A being the brightest and Z the least light).

LIGHTCODE is a moderated, open membership, public read access (anyone can view files), only members can post (including photos), mailing list for those interested in a discussion of light as it relates to the Universal Light Code (ULC)tm. The decoder for the ULC is available at the Black Cat Photo site: as a freeware nomograph called the Black Cat Exposure Tetrad or a commercial dial-type version called the Black Cat Extended Range Exposure Guide. A recent addition is Frank Kujawski's interactive decoder for the ULC located here: