A RAW file contains the original image information as it comes off the sensor before in-camera processing. RAW image files must be processed with special software before they can be viewed or printed. With RAW files, you have the ability to modify the white balance, exposure, color, contrast, brightness and sharpness as you see fit before you convert this data into the standard JPEG or TIFF format.
RAW files have 12 bits of available data so you are able to extract shadow and highlight details which would have been lost in the 8 bits of JPEG or TIFF files. Professional photographers import RAW files directly into editing programs like Lightroom or Photoshop.