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converting pdf to fax tiff (get a bit better quality?)
Posted: 2012-05-30T08:17:16-07:00
by mmlenz
I'm using the following:
convert -density 204x196 -units PixelsPerInch in.pdf -alpha remove -resize '1728x2156!' -compress Fax %d-out.tiff
Which is a command I found in another post on the forum. The resulting tiff file isn't horrible but the text is a bit jagged. Any recommendations for parameters to try to smooth things out a bit?
Re: converting pdf to fax tiff (get a bit better quality?)
Posted: 2012-05-30T09:55:39-07:00
by fmw42
double your input density. it will be slower, but should render better. If that is not good enough, increase the input density further.
Re: converting pdf to fax tiff (get a bit better quality?)
Posted: 2012-05-30T10:00:06-07:00
by mmlenz
yeah, I bumped it to 4x that and there was little or no improvement. I'm wondering if maybe my pdf viewer applies some kind of smoothing to the actual image. I used pdfimages to extract some of these and they look nearly identical to the output produced by convert.
Re: converting pdf to fax tiff (get a bit better quality?)
Posted: 2012-05-30T10:16:40-07:00
by fmw42
Can you post a link to one of your (smaller) pdf files? perhaps it has to do with the fax compression, which likely binarizes the image, thus the jaggedness. You could try to make the image binary using -monochrome before the output, if that is the issue, and see if that helps as I believe -monochrome will dither the result. But I am no expert on fax format tifs.