The RAW deal

What is a raw file?

A raw file contains the virgin data captured by the digital camera sensor before it has been converted to JPEG or TIFF. Cameras that create JPEG or TIFF files process (and in the case of JPEG files, compress) the sensor data. When working with raw files, the file is not compressed or processed in the camera—instead, the user has complete control over the conversion settings. For example, white balance is not applied to the raw file but is stored with the file so the software can default to the originally intended setting. Other information contained in a raw or DNG file includes standard EXIF metadata (just like in JPEG files), date, time, camera used, and camera settings.

Benefits of raw files

Some of the benefits of shooting raw include:

• Smaller files than uncompressed TIFF
• Does not have the artifacts of compressed JPEGs
• Many key camera parameters, such as white balance, can be modified even after the image is captured
• You have complete control over conversion settings rather than letting the camera decide
• Access to 16-bit data for greater detail and fidelity
• Flexibility of converting a single file using multiple conversion settings

What is Digital Negative (DNG) format?

Digital Negative format is an openly published specification that not only is supported by Adobe, but is also freely available for other software and hardware vendors to support. Adobe provides a free DNG convertor application for the supported cameras.

Unlike most manufacturer-specific raw formats, the Digital Negative is an openly published specification that not only is supported by Adobe, but is also freely available for other software and hardware vendors to support. Consequently, it can be a safer file format to use for long-term archival purposes. Archiving your file as a digital negative eliminates worries that the raw file will no longer be readable once the camera that created it becomes obsolete.

The Digital Negative specification allows for not only all of the pixel information stored in current raw formats, but also can include a JPEG to convey the intended appearance of the image. It also retains all of the additional, proprietary metadata that many manufacturers include in their raw file formats.