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Re: [OT] scanned files are large in size




On Friday 04 January 2019 12:26:07 Brian wrote:

> 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@xxxxxxxxxxxxxxxxx> 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
> this.
>
> BTW (for completeness), what machine was scanned_in_office.pdf
> produced on?

If I take a screen snapshot that might be of interest to my bunch, I 
usually run it thru gimp, exporting it as a jpeg, increasing the 
compression until I start to see artifacts/errors in the preview image, 
then go back up in size till I can't see them anymore, then export to a 
more understandable english name.  By this method I have pulled in an 
image from my camera that was a gigabyte+ when unpacked from its "jpeg" 
output, and smunched it down to 2 or 3 hundred kilobytes for sending 
over the net. And I'm still sending a far higher quality of image than 
I've ever received from a winders machine sending me 25k jpegs. The 
proper description of those when being kind is fugly.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>