Re: Books online...

[mjmahon@aol.com (Michael J. Mahon)]

Scott Alfter wrote:

>In article <1n68iv0frmrdvivdme2edvg64ta5e0trv8@4ax.com>,
>Chris Morse  <chris@cosmicwolf.com> wrote:
>>At 300 dpi and JPG compression, the images are still about 1.1MB for
>>each page.  The resolution is great, but that's still a lot of space.
>>I'll keep the high-res scans but I'll probably resize them all to the
>>smallest legible resolution (and use GIF , which will save a lot of
>>space on top of that too.)
>
>You should use PNG or (better still) TIFF...while GIF no longer has patent
>issues to deal with (the LZW patent expired last month), you'll get better
>compression with the other formats.  TIFF also provides for marking the scan
>resolution within the file, so you can more easily get a 1:1 printout if you
>need it.

The most important thing to enable great compression is to adjust
the "levels" of the photo so that the blacks are saturated and the
whites are pure.  Then reduce the number of "colors" to 16 or less
and convert to .gif.  The compression will be excellent, and there
will still be some anti-aliasing grays to clean up jaggies.

If the level equalization step is not taken, then much of the
compressed file will be used for representing the "noise" in
the paper grain and the ink irregularities.  (Of course, any
photo of a page should be cropped to eliminate any "busy"
background, which will only waste bytes.

I tend to print things out at the size I want, not the size they
were when I scanned them, so .tif doesn't buy much in my book.

-michael

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