manuals in pdf (resolution, compression)

From: Paul Koning <pkoning_at_equallogic.com>
Date: Mon Jun 28 09:19:01 2004

>>>>> "Tom" == Tom Owad <owad_at_applefritter.com> writes:

 Tom> I have a lot of manuals I want to scan and am trying to decide
 Tom> upon the best format. I'd like some opinions on the following
 Tom> scans of a 128-page Franklin AceWriter manual.

 Tom> On the low end is a pdf of bitmap images. It's hideous, but
 Tom> only 3.5 MB.

 Tom> The high end is a 40 MB pdf of jpeg images. This one's easy on
 Tom> the eyes, but is an awfully large download and I'm wondering if
 Tom> it might not print as nicely as the bitmap.

 Tom> In the middle is a pdf of compressed jpegs at 15 MB. This looks
 Tom> good to my eyes, I just wonder about using compressed jpegs for
 Tom> archiving...

JPEG is NOT designed to handle bitonal (black and white) source
material. It's designed for continuous tone images such as photos.
That's where the name comes from and that's what its algorithms are
designed for.

If you apply it to a bitonal image, several things will happen.

1. The files end up very large.
2. The images end up blurred and full of compression artifacts.

The correct way to compress bitonal images is with a compression
algorithm designed for that job. TIFF, GIF, and PNG are examples.
Not only will you get better quality, but you'll get smaller files.

          paul
Received on Mon Jun 28 2004 - 09:19:01 BST