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Re: [OT] scanned files are large in size




On Tue 01 Jan 2019 at 12:34:38 -0500, kamaraju kusumanchi wrote:

> A scanned document from Canon pixma mx870 printer is significantly
> larger compared to the same document scanned on a different scanner.

Which is...?

> When I look at both the images side by side on a PC, there is no
> visual difference between the two. I am trying to understand the
> underlying cause and fix it if possible.

You could mention which scanning software you used and what the
setting for the output file format was.

> As shown below, scanned_in_office.pdf is 332Kb, scanned_on_mx870.pdf is 1.7 Mb.
> 
> % ls -al scanned_in_office.pdf scanned_on_mx870.pdf
> -rw-r--r-- 1 rajulocal rajulocal  331796 Jan  1 11:54 scanned_in_office.pdf
> -rw-r--r-- 1 rajulocal rajulocal 1775460 Jan  1 11:48 scanned_on_mx870.pdf
> 
> Both are are scanned at 600 dpi. The only difference I see is in bpc,
> enc fields.
> 
> % pdfimages -list scanned_in_office.pdf
> page   num  type   width height color comp bpc  enc interp  object ID
> x-ppi y-ppi size ratio
> --------------------------------------------------------------------------------------------
>   1     0 image    5104  6600  gray    1   1  ccitt  no         7  0
> 601   600  183K 4.5%
>   2     1 image    5104  6600  gray    1   1  ccitt  no        14  0
> 601   600  138K 3.4%
> 
> % pdfimages -list scanned_on_mx870.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         8  0
> 600   600 1066K 3.2%
>   2     1 image    5100  6600  gray    1   8  jpeg   no        14  0
> 600   600  665K 2.0%
> 
> Questions:
> 1) Does the large file size have anything to do with the printer
> itself? Is there anything I can do (ex:- update the driver/firmware or
> something)?

Not at all; the printer has nothing to do with it. Printing is printing.
Scanning is scanning.

> 2) Is the difference in image sizes due to the bpc (1 vs. 8) or
> encoding (ccitt vs jped) fields?

Could be.

> 3) If yes, how to change them?

One file is in (I think) tiff format. The other isn't. You didn't scan
like and like from both devices.

-- 
Brian.