Data File Types for Photos
File types for digital photos vary in the way each reproduces image quality, as well as the amount of space each demands on a hard drive. Data file types that work well in one situation may be the worst choices in another. For instance, while photo images saved as JPEG file types are excellent for emailing images, they are terrible choices for long term photo archiving.
Choosing the wrong data file types can cause serious problems, including the loss or distortion of saved information. For example, just as archived image files can be corrupted if the incorrect data file types are used, so too can images saved in larger file types tie up an email program for hours.
The four main data file types used to store photos and images are JPEG, TIFF, GIF and PNG files. The file types that digital cameras and imaging software support depends on each product’s specifications.
Storing Images as JPEG Files
JPEG, short for Joint Photographic Experts Group, is a file type that most digital cameras and imaging software support. In fact, JPEG files are the types of image files that are used most often on the Internet. Because of their small size, JPEG files allow images and pictures to be easily emailed and/or uploaded to websites.
JPEG files are smaller than most other file types because the images they store are mathematically compressed: the JPEG file may be one-tenth the size of the original data file. Because file size is an important consideration when emailing image files, JPEG data files are the best way to email images quickly without jamming up someone’s email program or overloading his inbox.
However, the speed at which JPEGs can be emailed or loaded on web pages comes at a price that serious photographers are often reluctant to pay. When a JPEG file compresses data, it alters the image’s pixel data, deleting small areas that cannot be compressed easily. As a result, subtle variations in color and detail are often lost during JPEG data compression.
Every time a JPEG file is saved, the compression process slightly degrades the image quality. Moreover, this effect is cumulative: repeatedly modifying JPEG file types results in corrupted files, as well as poorer and poorer image quality.
Because JPEG file types degrade with use, they are called “lossy” files. The term lossy describes the fact that each time a JPEG is resaved some of the image quality is lost. Consequently, while JPEG photo file types are excellent for quickly emailing photos or uploading images, they’re not recommended for long-term archiving of image files.
TIFF Data File Types
TIFF date file types, or Tag Image File Format, are “lossless” data file types, meaning that no image quality is lost when a TIFF file is saved and compressed. Professional photographers and graphic designers use TIFF files more than other photo file types. However, mid-range digital cameras may not have enough memory to support TIFF files.
Image quality has made TIFF files the standard data file type for archiving images and photos. The only negative aspect of TIFF files is their size. Because they save all of the pixel information in data compression, TIFF files are much bigger than JPEG files. As a result, TIFF files require large amounts of memory to store images. Keep in mind that a compressed TIFF file is not appreciably smaller than an uncompressed file. For people concerned with the corruption of photo files, however, TIFF is a reliable choice.
PNG Photo File Types
PNG (Portable Network Graphics) are also lossless types of data files. Like TIFF photo files, PNG image files are suitable for long term photo archiving. Although the average viewer may not notice the difference, PNG data files have even better lossless compression (they reproduce the images at a better quality) than TIFF files. PNG files are supported by a variety of imaging software programs.
GIF Data File Types
While GIF (graphic interface format) data file types are commonly used for graphics and digital images, they are not well suited to storing photo files. GIF files are restricted to a 256-color palette, making them insufficient to accurately reproduce photo images. Graphic designers regularly use GIF files for images and logos with limited colors. Similarly, GIF files’ smaller sizes make them ideal for website use.
Image Data Files and Photographers
Choose among the various types of data files according to the way the photo or image will ultimately be used. If you’re archiving photo files, TIFF and PNG are the best choices. However, no one wants to receive emails containing such large files that tend to stall computer programs and flood inboxes. Conversely, the smaller size of JPEG files makes them better suited for online use but not well-suited for protecting image quality.
The best way to handle the differences among data file types is to use both. Save master copies of image files using TIFF or PNG. Then, if you need to take advantage of JPEG files’ compression abilities, copy the master image and convert it into JPEG format. By doing this, files can be easily emailed while you safely retain quality archival copies.
Digital Compression of Image Files Digital compression uses complicated algorithms and mathematical formulas to compress digital images. In fact, digital cameras digitally compress files as a standard part of data storage in order to consume ...