[Tfug] Hand scanner recommendation?

[John Karns]

On Sat, Jan 2, 2010 at 3:31 PM, Bexley Hall <bexley401 at yahoo.com> wrote:

> TIFFs actually *can* use compression.  But, *lossless* (vs the
> lossy compression used in JPEGs).  However, you tend to end up with
> bigger files... (of course, there are pathological cases that
> defy each of the above assertions)

A common problem I remember having encountered in dealing with TIFF
images is that I often used to find that none of the image viewing
apps I had installed would successfully open / view more than about
70%-80% of the images I was dealing with.  (This was about 15 years
ago, so things may be different now.)

Without having info on hand to corroborate my supposition, I
attributed it to the existence of several different compression
specifications used to create files labeled as being TIFF.  I seem to
remember having an app to create them which presented various
compression format options.

======================================
... Just looked it up on wikipedia:

TIFF is a flexible, adaptable file format for handling images and data
within a single file, by including the header tags (size, definition,
image-data arrangement, applied image compression) defining the
image's geometry. For example, a TIFF file can be a container holding
compressed (lossy) JPEG and (lossless) PackBits compressed images. A
TIFF file also can include a vector-based Clipping path (outlines,
croppings, image frames). The ability to store image data in a
lossless format makes a TIFF file a useful image archive, because,
unlike standard JPEG files, a TIFF file using lossless compression (or
none) may be edited and re-saved without losing image quality. This is
not the case when using the TIFF as a container holding compressed
JPEG. Other TIFF options are layers and pages.

TIFF offers the option of using LZW compression, a lossless
data-compression technique for reducing a file's size. Until 2004, use
of this option was limited because the LZW technique was under several
patents. However, these patents have expired.

When TIFF was introduced, its extensibility provoked compatibility
problems. Every TIFF reader was required to read BaselineTIFF, but
Baseline TIFF did not include JPEG or LZW compressions (see above).

======================================

I found other image compression schemes to be easier to deal with,
such as GIF.  However, at the time, there was a movement away from
distributing images as GIF due to an enforcement of royalty collection
by the company that held the patent (Unisys).

-- 
John Karns