Re: Scanning?

[Mike Maginnis <maginnis@tarnover.org>]

On 15 Apr 2005 13:38:22 -0700, Eric Smith <eric@brouhaha.com> wrote:

>Mike Maginnis <maginnis@tarnover.org> writes:

--<snip>--

>
>For pages that only contain text and line art, *please* use Group 4 fax
>lossless compression.  This is a natively supported format in TIFF,
>Postscript, and PDF files, and results in 30K-50K sizes for a typical
>page (though more for pages with lots of small type or fine drawing
>details).  Any good scanning software can do it.  Since it's lossless,
>the quality is identical to the original scan.
>
>However, G4 compression is not good for photographs or other continuous-tone
>images, because that's not what it's designed for.  Pages that have such
>images (other than relatively unimportant incidental ones) should be
>compressed with JPEG compression, which is what it sounds like you've
>been doing.  Unfortunately JPEG compression blurs text and line art.
>
>Ideally, for pages that consist of a mix of text and line art, and
>continuous-tone images, you'd use a graphic editor (e.g., Gimp or
>Photoshop) to separate the continuous-tone images into a separate layer,
>apply JPEG compression to those only, and G4 to the text and line art.
>Then you can composite the result in either Postscript or PDF.
>
>That process yields really nice looking results, but takes a lot of
>work.
>
>Eric

Ok, now we're definitely out of my depth.  I have no idea what "Group
4 fax" is, or indeed how to apply it to a scanned image or a saved
TIFF file.

The proprietary scanning software that came with the OneTouch is the
only thing that will talk to the scanner.  Its rudimentary and lacks
all but the most basic functionality.

"separate the continuous-tone," etc.  No idea how to even begin to do
this.  My Photoshop skills are tenuous at best and I've manage to
screw up countless images trying to make layering work properly.

Sounds like a time consuming process for the thousands (?) of pages
that need to be scanned for a complete set of archives.  At my level
of scanning prowess, it would almost make more sense to type each
issue in by hand... I may have to do that with the 11x17" issues
anyway.

These sound like good suggestions, but I have no idea what to do with
them...

- Mike
maginnis@tarnover.org