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Re: [OT] scanned files are large in size

On Wed 02 Jan 2019 at 22:56:22 -0500, kamaraju kusumanchi wrote:

> On Wed, Jan 2, 2019 at 9:23 PM David Wright <deblis@lionunicorn.co.uk> wrote:
> >
> > On Wed 02 Jan 2019 at 14:44:14 (+0000), Brian wrote:
> > >
> > > I'm intrigued; I hadn't realised that conversion of the scanned image
> > > for some vendors' devices took place on the device itself. How do you
> > > know this happens? It is the frontend to SANE (xsane or scanimage, for
> > > example) which I've always associated with image aquisition conversion.
> >
> > It really is rather easy. You insert a USB stick into the scanner,
> > press scan, and later observe that a JPEG or PDF file has appeared
> > on the stick, as appropriate.
> >
> Yes, that is precisely what I did. Stick a USB into the scanner and
> press the scan button.

My HP Envy 4520 has no such button. There is an option for scanning to
the computer, but software is required on the computer to do that and
HPLIP does not provide it.

Anyway, I managed to persuade the device to give me the PDF it would
have sent to a USB stick if the facility had existed (the device has
Apple's AirScan). If it matters, the PDF does not have any Creator or
Publisher information and doesn't contain any embedded or subset fonts.

Scanned at a resolution of 600:

brian@desktop:~$ pdfimages -list out.pdf
page   num  type   width height color comp bpc  enc interp  object ID x-ppi y-ppi size ratio
   1     0 image    5100  6600  gray    1   8  jpeg   no         1  0   600   600 2090K 6.4%

ps2pdf reduces the 2090K by about 50% to 1051K.

A different scanner device and source document, of course, and maybe
different methods of PDF production, so I wouldn't read too much into

BTW (for completeness), what machine was scanned_in_office.pdf produced


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