At 20:38 19/04/05 +0100, you wrote:
>And has any one any suggestions on what you can with a photo of a very dirty
>parchment document to increase the contrast between dirt and ink so that it
>is easier to read?
Use the histogram correction tool in Paint Shop Pro or Photoshop (I don't
think this tool is available in Photoshop Elements or LE) to *first*
increase the gamma then adjust the highlight level and/or the contrast level.
If the dirt is mostly a different colour to the ink (although it probably
isn't!!) then use the colour replacement tool to change the dirt to a
similar shade as the clean parts of the parchment. (This 'trick' works
better with documents written in blue ink on foxed or stained paper. The
brown is sufficiently distinct from the blue ink that it is comparatively
easy to change the stains to a more paper-like colour while leaving the
blue ink unchanged. A final 'play' with the histogram adjustment tool
usually makes such documents much more legible.)
One chapter of my recently published book 'How to Write and Publish Local
and Family History' is devoted to improving images, especially optimising
for publishing (whether offset or digital printing or on Web sites and
CD-ROMs). Details at www.hoap.co.uk/general.htm#HoTo
Bob
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