I will take a quick look at file formats for photos and images, since the names of these will be repeated many times in the following text.
Graphics Interchange Format (GIF): is a bit-mapped format that is very useful for transmitting images over the Web. It is better for scanned illustrations and animation rather than photos, since it achieves some compression by limiting them to 256 colours.
Joint Photographic Experts Group (JPEG) or (JPG): is a compression technique that discards information that the human eye cannot detect, however, unlike GIF, it can support up to 16 million colours and is suitable for transmitting photos over the Web.
JPEG 2000: is a more recent, updated and improved version of JPEG and it offers a higher compression ratio. In addition, it eliminates some of the “blurry” and “blodgy” features that characterized images in the original JPEG. It also offers better progressive downloads of images.
Portable Network Graphics (PNG): is another compression technique which can reduce file sizes by up to 25% more that GIF, however, it cannot support animation.
These formats are very useful since file sizes are smaller than is the case for other formats, and this in turn helps to speed up file downloads over the Internet.
Tagged Image File Format (TIFF): can be used for storing photographs, line art scanned images, etc. One advantage which this file format has over JPEG is that it can be edited and then saved without any deterioration due to compression.
Raw Files: refers to the image file formats in which pictures are captured in a number of cameras made by different manufacturers. It consists of the unedited, untouched pixel image (equivalent to a “digital negative”) stored in your digital camera. If your camera can record in 12 bits of data, you can obtain 4,096 brightness levels (mathematically expressed as 212). If it records in 14 bit, then it offers 16,384 brightness levels (214).
I should caution you that if you use your in-camera’s conversion to JPG, your images will be converted to the camera’s 8 bit mode and you will only get 256 levels of brightness. On the other hand, if you take the RAW image and use a RAW conversion program (such as CameraRaw or Capture One) and save your images in TIFF format, then your images will spread out into the 16 bit workspace.
Obviously, the higher the brightness levels, the higher the quality of your image. The downside is that your file sizes become very large and, if you want to take a lot of pictures, you may want to use your in-camera conversion to JPG which will keep your file sizes small.
Digital Negative (DNG) file format: is for archiving files generated in Raw format by cameras made by different manufacturers and also to accommodate the storage of pictures from cameras of the future.
Adobe offers a free converter which will convert Raw files from many popular models of digital cameras. Adobe is also committed to maintaining this format so that such files can be imported into any future software programs it develops, as well as the latest versions of Photoshop.
There are four basic processes in digital photography.
The first involves image capture which involves the nondestructive capture of a picture in digital format. I would recommend that you save your photos in their original Raw format, as discussed above.
The second involves the import of your JPEG or Raw images and you can edit or enhance them using some of the programs by Adobe, Corel or Microsoft. Then, you can save your images in JPEG, TIFF and PNG formats.
The third is to send your images out for print, print them yourself on a photo printer or view them electronically.
Finally, take steps to make sure that your original images and altered images are stored in a safe manner i.e., saved on a CD-ROM or DVD disc so that you can still access them even though your computer may suffer a hard drive failure.