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Re: [BKARTS] File format for colour photocopy



on 1/24/03 1:21 AM, Jennyhogben@xxxxxxx wrote:

> The local printers suggested scanning images at 400 dpi but there is some
> disagreement over the type of file - JPEG, bitmap, or is there a better
> format?   Also, is 400 dpi a high enough resolution for a photocopier?

It depends on the content of your book and type of color printer (or
photocopier) you will be using. The standard is usually 300 dpi, which will
give you excellent detail for images, but may not be adequate for type
smaller than, say, 12 points.

Scanners will usually output a jpeg as their native format. Again, depending
on your content, you will choose a quality factor, usually on a scale of 1
to 12, with 12 being best. I use 12 at 300 dpi for most work.

Scans usually have to be corrected in an image editing program such as
Photoshop in order to get better color values. Once corrected, they must be
saved as TIFF or PSD (Photoshop native format). If you save them as jpeg
over jpeg, quality will decline, often drastically.

The best way to do this is to experiment with representative pages. Make
trial scans, correct them if necessary and print them on the paper or other
medium you plan to use for the final version.

Be aware that output of color printers such as the Xerox Phaser will not
match your originals exactly. Depending on the length of the run, there may
also be considerable color drift due to the drum getting hot, as well as
other factors.

You have to look at the printed copy as if it were a separate work of art,
without reference to the original. Scanning works of art and printing them
from the scans is an art in itself. You'll find that some pages never work
the way you want, no matter how you scan them or manipulate the scan. When
that happens, you have to accept the best of what you get, or do the page
over again so that it is easier to scan.

Be prepared to learn a lot.

--
JULES SIEGEL Apdo. 1764, 77501 Cancun Q. Roo Mexico
http://www.cafecancun.com

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