[Sugar-devel] De-yellowing page images?

[James Simmons]

Sean,

Great!  I KNEW this would be a good group to ask!  I tried using
greyscale in GIMP and got pretty good results, and I'll try this too
when I can.  I'll definitely write up all these tricks in the book.
I'm already recommending Image Magick for creating PDF's so this tip
will be a natural.

Thanks again,

James Simmons


On Mon, May 10, 2010 at 10:36 AM, Sean DALY <sdaly.be at gmail.com> wrote:
> James - use imagemagick's -modulate switch:
>
> convert -modulate 150,0,0 BoysAviation_008b.jpg BoysAviation_008b.greyscale.jpg
>
> 150% brightness, 0% saturation, 0% hue will give you the result attached.
>
> http://www.imagemagick.org/script/command-line-options.php#modulate
>
> Better results than the -monochrome switch; with -modulate you can
> tune the conversion to the scan(s) in question
>
> Sean
>
>
>
> On Mon, May 10, 2010 at 5:19 PM, James Simmons <nicestep at gmail.com> wrote:
>> I'm asking this question here because at the moment I don't know where
>> else to ask.  The question relates to the Reading And Sugar book I'm
>> doing.
>>
>> I'm scanning in book pages of a book printed in 1928.  The pages are
>> quite yellow, but readable.  A sample is at:
>>
>> http://en.flossmanuals.net/bin/view/ReadingandSugar/ScanningBookPages
>>
>> I'd like to lighten or remove the yellowing from the pages to make the
>> book more attractive.  Maybe leave the text alone and replace
>> everything else with white.  I tried different things with GIMP
>> without much luck.  Any ideas?
>>
>> Thanks,
>>
>> James Simmons
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>