Black
Grey Yellow
Green
Blue
(Change background color on Mouse-Over above)
Originally developed by Compuserve® years ago, it fulfilled a need for compressed file sizes that could quickly be sent over the web or exchanged on a "bulletin board". In those early years, video boards were limited to 256 colors and modems were ponderously slow. GIF fulfilled a need at that time for a compression utility for the transmission of simple color graphics. Photographic images today are comprised of millions to billions of colors ! Photographic images saved in GIF result in the loss of all but 256 colors ! It is suitable today for such images as 2 color line art and simple color graphics. GIF does however, support transparency and supports simple web animation as well. GIF however, is limited to only 256 colors and thus is not suitable for photographic images. Never save your master photographic quality image in GIF.......
Undoubtedly the best format for sending images over the Web, because the file is so wonderfully small and one is not limited (unlike GIF) to 256 colors ! Jpeg will often compress to a size 1/10th the size of the original, and some images with solid color backgrounds will compress to as much as 1/20th ! Yet there is a "price to be paid" for this marvelously compacted file size...... related pixels with similar color/luminance values are simply tossed out onto the digital "heap"..... never to be recovered again. The "blocky" appearance result is often referred to as image compression artifacts. Sadly, if that isn't bad enough, the losses accumulate with each compression/de-compression cycle. Thus Jpeg is best suited for sending images over the Web, and should not be used to archive your master images. If the "damage" has been done, and your only image file is already in jpeg format, your best off saving it back in TIFF or PNG...... If space is critical or there is no other option, then less additional "damage" will be done by saving the file back in JPEG at the very same value of quality (compression value) - NEVER a lower value ! If you are forced to use Jpeg, then be sure to select the highest quality setting !
JPG has continued to evolve however. The recent JPG 2000 standard allows saving images using a lossless compression scheme.
Bitmap files are loss-less like TIFF and PNG. It will deal with 24 bit color, but bmp cannot compress that color depth. Though it effectively compresses 8 bit data which is ok for graphics and line art (256 colors or less), it does not handle well the continuous tones and graduations of photographs.
Similar to BMP, it is a loss-less format, however the compression is rather low for photographic work. Both BMP and PCX files suffer a major disadvantage, in that they cannot be shared with Macintosh users. They are endemic to the PC/Windows environment.....
Though Loss-less, the files may not be shared with Windows applications....
Tiff has been the format of choice for several years. Developed by Aldus (now owned by Adobe®), The .tif file is the most widely accepted and supported across various computing platforms. Tiff generates very large file sizes and is a "loss-less" file format. As of today, it is the most popular format for saving precious master images.
PNG came about as a replacement for GIF due to LZW licensing troubles, as well as GIF being limited to only 256 colors. PNG supports both 24 and 48 bit color depth, as well as it being a completely loss-less compressed file format. The compression technique employs the "Zip" method, like the popular PKZIP/UNZIP® compression routines. But PNG goes even beyond that ! It incorporates software "filters" that enhance the compression of smooth gradients typically found in photographs. Resulting file sizes are substantially smaller than any of the other loss-less formats, and PNG is the answer to a prayer ! Originally, only professional image editing packages supported it, but today, it has been widely adopted by nearly all software developers. Though JPG remains the best format for sending over the web due to it's small size, Master image files should always be stored in a lossless format.
RAW (exactly as its' name implies: a Raw Data Format)
A high quality uncompressed format representing all the CCD was able to capture.
Pluses: there are no artifacting problems or losses of any kind.
Negatives: The file sizes can be immense. Imported raw files will not display as thumbnails in Windows. The major drawback is that none of the manufacturer's can yet agree on a single RAW standard. Though similar, every manufacturers' RAW file will often be different from the others.
HD Photo
As of March 2007, being pushed by
Microsoft as a replacement for the 15 year old JPG technology. Microsoft claims
file sizes half those of JPG with less damage done each time the file is opened
and saved. HD Photo will also purportedly support a lossless option. Too early
to tell how this will be accepted, or what impact it might have on converting the
"K-Zillions" of JPG's over to HD.
The printing of large images calls for making the best use of every pixel originally captured. Though almost anything will do when printing a 4x6" snapshot, enlarging it up to its' full potential requires a certain attention to detail if the best results are to be obtained. Enlarging an image for large format printing results in the good data as well as the bad/missing data and accumulated artifacts to be enlarged as well.
Thus.....
Master images should always be saved
in either TIFF or PNG.
Web photos are best sent in JPEG where small size and color retention is the only
desired goal.
Use GIF for web animations, where a transparent palette color is required or on
simple color graphics. Beware: it is limited to only 256 colors. Once "lost", those
other millions to billions of colors can never be recovered.
(This is an image intensive page that will take approximately 70 seconds to download on a 28.8k connection)
Last Modified: March 12, 2007
Terms and Conditions on using this siteMade in Maine
Since 1978 - Copyright © 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Video Interchange
Video Interchange - PixelPrinters
92 George Luce Rd
Waldoboro, Maine 04572
207-832-5064
Northeast Region - New England
