Re: [Gimp-user] resolution, size when extracting from pdf vs. imagemagick

[Joel Rees <joel rees gmail com>]

2015/07/07 16:55 "Christian Mandel" <c mandel gmx net>:
> For this use case,

Well, actually, even IM's default 72 px/in would have done my present job.
However,

> I would suggest using the pdfimages program (from xpdf I guess)
> (with the -j option to preserve embedded jpg) to extract the original
images.

this is all useful information.

> The import in gimp will always "render" the pdf, what will always scale
the original image,
> unless you hit the exact resoultion/size.
> Even then some quality will be lost since the pixel data from the
rendered image will be taken and not the original information.
> IIRC, neither IM nor Gimp will look into the pdf "container" to check the
original jpeg's resolution, they assume a default resolution which you can
change as Pat suggests.
> Best regards
>
> Chris

Thanks.

> Am 07.07.2015 um 09:00 schrieb Joel Rees:
> > I have a pdf of scanned images, theoretically jpeg images, and the gimp
> > will offer me a selection dialog, from which it will import them
> > individually as 1304x932 at 100 px/in. (This is odd, because I selected
> > 300dpi at scan time, so the images should be 3 times that pixel density.
> > But, then, 22Mb for 36 images is not 13" x 9" at 300 dpi, unless heavily
> > compressed.)
> >
> > ImageMagick's identify -verbose tells me the same are 1032x728 at 72 dpi.
> > If I use ImageMagick's convert to extract them, that's how they end up.
> >
> > Anyone have an idea what's happening?
> >
> > Joel Rees
> >
> > Computer memory is just fancy paper,
> > CPUs just fancy pens.
> > All is a stream of text
> > flowing from the past into the future.
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