… for Codecs & Media

Tip #650: What is a Raw file format

Larry Jordan – LarryJordan.com

Raw is not an acronym, it simply means “unprocessed.”

Raw is an image and video file format used by many high-end and professional digital cameras. RAW files are considered to be the best form of image file, since it does not process the picture, leaving total control of the editing to the user.

A camera raw image file contains minimally processed data from the image sensor of either a digital camera, a motion picture film scanner, or other image scanner. Raw files are named so because they are not yet processed and therefore are not ready to be printed or edited.

Raw image files are sometimes incorrectly described as “digital negatives”, but neither are they negatives nor do the unprocessed files constitute visible images. Rather, the Raw datasets are more like exposed but undeveloped film.

Like undeveloped photographic film, a raw digital image may have a wider dynamic range or color gamut than the developed film or print. Unlike physical film after development, the Raw file preserves the information captured at the time of exposure. The purpose of raw image formats is to save, with minimum loss of information, data obtained from the sensor.

There are dozens of raw formats in use by different manufacturers of digital image capture equipment.

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