Since we have been exploring photo editing we should also discuss the computer image file formats available to us and consider why there are so many file formats. When you are ready to save an image you’re confronted with the decision of which format to use and image compression options.
Image file compression can be lossless or lossy. The lossless compression methods preserve a perfect copy of the original. That’s exactly what you want. Lossy compression should be avoided for originals. Note that several file types that are thought of as lossless can be optionally set to provide file compression.
Image file formats that can be lossless, if you make the correct settings, include .TIFF, .RAW, and .PNG. .JPG files are most often lossy. This format is a common image file format in digital cameras or is available as a format for saving files on your computer. It’s usually ok to work with .JPG at this point if you prefer. As long as the compression factor is minimal you won’t notice any degradation of the image. Be certain that your software allows for adjusting the compression level and learn how to use this function. The .JPG file format will become very useful after you have your favorite originals safely saved in the best quality format possible with your software.
The basic trade off you should consider is the continuum of higher image quality and larger file size versus smaller file size and reduced image quality.
When you have the version you want to save in your computer or make prints from you have the luxury of saving it in an uncompressed format. When you decide to incorporate the image into a web site you will want to trim the file size through compression to insure the photo snaps onto the screen when the page loads. Most social networking sites will compress your picture file for you when you upload it to them.
Compression equals loss of image information. A small to moderate level of compression can provide benefits without sacrificing a noticeable level of quality. On the other extreme high levels of compression will destroy your image. The top image is a .jpg saved with 1% compression and then below with maximum compression. Your digital images are composed of many small single-colored square display elements called pixels. Compression artifacts are a visible distortion of the image which results from excessive lossy file compression.
For online image presentation limiting the pixel count by reducing the dimensions of your image is one option that may allow you to maintain acceptable image quality while still maintaining a smaller file size.
RAW Format – Your camera may be able to shoot photos in RAW format. RAW files are the best way to preserve your original image information in a digital file. Shoot in RAW mode to gain the most control over your final image. For photo editing Photoshop, Paintshop Pro and other photo editing software can handle RAW files. Check your program’s feature list.