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Re: [OT] scanned files are large in size




On Fri 04 Jan 2019 at 13:41:50 -0500, Gene Heskett wrote:

> 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.

Perhaps I am missing something, but this appears to have nothing to
do with my post. If you missed the essentialness in this thread, it
is about scanning, not screen snapshots and cameras.

Please try to keep up.

-- 
Brian.