L
Leonard Evens
I am in the process of scanning a large number of documents, most of
text, but some of hand written notes. I'm using two scanners. One is
part of a commercial copier/scanner in my department, and the other is a
Canon DR-2050C. With the latter I can exercise some control to enhance
legibility, but that is harder with the department scanner since it
sends me e-mail with an attachment which must be examined later.
It seems plausible that one should be able to modify the resulting files
to enhance legibility when viewed with the Acrobat Viewer. But so far I
have not had much success with what I've tried. I've found software to
use to combine files, split them, rotate pages, and even to annotate
them. The Canon provided an OEM version of Acrobat Standard Edition,
which can do all the aforementioned things, but it can't enhance legibility.
Essentially everything I get is just black and white, but often the
black is just a light gray and hard to read. I would like to make it
darker. I've tried decomposing the pdf files into separate image files
and apply various image manipulation software to darken the blacks.
But generally the files produced are awful. So if I export a page as a
jpeg of tiff file, that the text in that file looks very digitized. If
I enhance it and conver it back to pdf, Acrobat shows me the same crummy
thing as what I had in the image file.
I would like to use programs which run under Linux such as Image Magick
which can convert back and forth and also enhance in a variety of ways,
but the results suffer from the problems I just described.
The one exception to this seems to be Photoshop under Windows, but I'm
not sure what's going on there. I don't have any greater luck using it
if the pdf file has been converted to jpeg of tiff files by ImageMagick
or another such program. But if I use Acrobat Standard Edition to
export jpegs, one for each page, those look the same in Photoshop (but
not in other viewers) as the pdf file did in Acrobat. On the other
hand, when something strange happens when I try to make adjustments.
The adjustments show up in the image window as long as the adjustment
tool is active, but revert to what they looked like before the
adjustment when I click OK in the adjustment window. I think the
adjustment is may actually be partially effective, but the change is not
dramatic.
I think that when Acrobat views a pdf file produced by a scanner is does
something different than simply displaying the pixels as some other
iamge viewer would do. Some information about that might be helpful.
Pdf files can be examined in a text editor since they are just modfied
postscript files, but doing so on those obtained by scanning are mostily
filled with binary coded data, i.e. image files. But as I noted above,
Acrobat is displaying them in some optimal way which other image
viewers don't use and perhaps Photoshop also employs the same viewing
mechanism.
In any case, I don't know how to use Photoshop in batch mode from a
command line to process a list of jpegs, so it would be impractical to
make modifications one image at a time.
Any suggestions would be appreciated.
text, but some of hand written notes. I'm using two scanners. One is
part of a commercial copier/scanner in my department, and the other is a
Canon DR-2050C. With the latter I can exercise some control to enhance
legibility, but that is harder with the department scanner since it
sends me e-mail with an attachment which must be examined later.
It seems plausible that one should be able to modify the resulting files
to enhance legibility when viewed with the Acrobat Viewer. But so far I
have not had much success with what I've tried. I've found software to
use to combine files, split them, rotate pages, and even to annotate
them. The Canon provided an OEM version of Acrobat Standard Edition,
which can do all the aforementioned things, but it can't enhance legibility.
Essentially everything I get is just black and white, but often the
black is just a light gray and hard to read. I would like to make it
darker. I've tried decomposing the pdf files into separate image files
and apply various image manipulation software to darken the blacks.
But generally the files produced are awful. So if I export a page as a
jpeg of tiff file, that the text in that file looks very digitized. If
I enhance it and conver it back to pdf, Acrobat shows me the same crummy
thing as what I had in the image file.
I would like to use programs which run under Linux such as Image Magick
which can convert back and forth and also enhance in a variety of ways,
but the results suffer from the problems I just described.
The one exception to this seems to be Photoshop under Windows, but I'm
not sure what's going on there. I don't have any greater luck using it
if the pdf file has been converted to jpeg of tiff files by ImageMagick
or another such program. But if I use Acrobat Standard Edition to
export jpegs, one for each page, those look the same in Photoshop (but
not in other viewers) as the pdf file did in Acrobat. On the other
hand, when something strange happens when I try to make adjustments.
The adjustments show up in the image window as long as the adjustment
tool is active, but revert to what they looked like before the
adjustment when I click OK in the adjustment window. I think the
adjustment is may actually be partially effective, but the change is not
dramatic.
I think that when Acrobat views a pdf file produced by a scanner is does
something different than simply displaying the pixels as some other
iamge viewer would do. Some information about that might be helpful.
Pdf files can be examined in a text editor since they are just modfied
postscript files, but doing so on those obtained by scanning are mostily
filled with binary coded data, i.e. image files. But as I noted above,
Acrobat is displaying them in some optimal way which other image
viewers don't use and perhaps Photoshop also employs the same viewing
mechanism.
In any case, I don't know how to use Photoshop in batch mode from a
command line to process a list of jpegs, so it would be impractical to
make modifications one image at a time.
Any suggestions would be appreciated.