Digital BW, The Print

Paul D. DeRocco writes:

> There are no file formats that I'm aware of that take an hour to compress,
> unless you write the compressor in interpreted Basic and run it on an Apple
> 2. ;-)

It's not difficult to imagine optimal compression taking an extremely
long time.  For example, in theory, you can examine an entire file as a
unit and use Fourier or Walsh transformations to optimally compress the
whole thing, and the resulting file may be small indeed, but it would
take an extremely long time to compress, and potentially quite a lot time to
decompress as well.

> However, in a more realistic vein, if you want to archive scanned images
> with no visible loss, but significant space savings, and you want to
> preserve more than eight-bit data, use JPEG2000.

Unfortunately, I don't have any decent support for JPEG2000 in my
image-editing applications, and obtaining it does not justify the cost
and nightmare of "upgrading" Photoshop or other tools to more recent
versions.