RAW Definition
RAW is not an abbreviation. It’s an image format that doesn’t use lossy compression. A RAW image holds the raw data that comes directly from the digital camera sensor. It preserves every single detail captured by the camera. Like the negatives in film cameras, RAW images need to be processed first. They then have to be saved in another image format, like TIFF or JPEG, in order to be viewed.
Unlike other image formats, RAW doesn’t have a defined standard. This means that if you have two different digital cameras with RAW capabilities,your post-processing software (like Photoshop) may be able to open a RAW photo from one camera, but may not be able to recognize the RAW image from the other, newer digital camera. That’s why post-processing software developers have to constantly update their programs to support newer digital cameras. In 2004, Adobe developed and started promoting the DNG (Digital Negative) format as a solution to this problem. You can read more about this on the Adobe DNG page.
Because RAW files require post-processing, which takes time, this format might be suitable only for professional photographers or serious amateurs who want to control every step of the image processing, like setting the white balance. Setting the latter when saving your photos in JPEG is not possible to do after you take the photo. This is one of the benefits you receive when saving your photos in the RAW format. It gives you more control.