Re: Image quality after resampling is not good - am I using the wrong options?

> The source images are in most cases PDF and often
300ppi with color

Try the following

  convert -density 400 too-big-scan.pdf -resize 50%
just-right-size.gif

Throw in a -monochrome or a +dither -monochrome to create
black/white images.
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That worked very well.  Thanks!

Questions:

1. Why set the density to 400 and then reduce the size?  I
got similarly
   good results by setting the density to 150 and leaving it
at full
size.

2. Here's the script I'm working on.  PDFs that contain more
than one 
   page result in animated GIFs with a frame for each page. 
Would it 
   be best to write a separate command to find any
multi-frame GIFs 
   and break them into separate image files?

#!/bin/bash
#
# Convert scanned images from various formats to 
# moderate resolution, black and white, GIF

for ORIG_FILE in `ls *.pdf *.gif *.tif *.jpg`
do
    echo "Converting $ORIG_FILE to
${ORIG_FILE%.*}.gif"
    convert -density 400 $ORIG_FILE -resize 50% -monochrome
${ORIG_FILE%.*}.gif
done

echo "Done"

# End of script

Peter Desjardins

> -----Original Message-----
> From: omicronpersei8imagemagick.org 
> [mailto:omicronpersei8imagemagick.org] 
> Sent: Monday, April 02, 2007 15:30
> To: magick-usersimagemagick.org; Peter Desjardins
> Subject: Re: [magick-users] Image quality after
resampling is 
> not good - am I using the wrong options?
> 
> > The source images are in most cases PDF and often
300ppi with color
> 
> Try the following
> 
>   convert -density 400 too-big-scan.pdf -resize 50% 
> just-right-size.gif
> 
> Throw in a -monochrome or a +dither -monochrome to
create 
> black/white images.
> 

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