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JPEG2000
compression
The JPEG2000 compression algorithm was released by an ISO
standardization committee in January 2001. It is based on the
existing JPEG specifications and adds three important things to the
existing standard:
It adds a wavelet-based algorithm to the existing JPEG compression
algorithms. This wavelet-transformation algorithm offers improved
image quality at very high compression ratios.
JPEG2000 is said to produce as much as a 20% improvement in
compression efficiency over the current JPEG format.
It also offers an optional lossless compression mode. Lossless
JPEG2000 files areabout half the size of the original.
Advantages of JPEG2000 compression
JPEG2000 is a very efficient compression algorithm. It has mainly
been developed for use on the internet.
The addition of a lossless compression mode is interesting for
prepress use.
Disadvantages of JPEG2000 compression
Even though I was a fan of the algorithm for some time, most people
I know have reverted back to using regular JPEG compression for 3
reasons:
Compatibility with legacy systems: only recent workflows or computer
applications can deal with JPEG2000 compression. If you need to
distribute data, this can be a real showstopper.
JPEG2000 is a resource hog: compressing data requires lots of
CPU-horsepower
At compression ratio’s below 25:1, the wavelet-based algorithm
produces less blocky but somewhat less detailed images compared to
regular JPEG compression. Too much compression is never a good idea.
How to save Jpeg 2000 files in Photoshop CS3
Next to the Jpeg2000 compression algorithm, there is also an
associated Jpeg2000 file format. There are actually two of them: the
regular JP2 file format and an extended JPEG 2000 format which uses
the .jpf extension. By default Photoshop cannot write these file
formats. A plug-in to add support for them can be found on the
installation CD in Goodies/Optional Plug?Ins/File Formats. Copy the
plug-in to Adobe Photoshop CS3/Plug?Ins/File Formats. |
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