[reportlab-users] Writing smaller image-only PDFs

[matt wilbert]

How big are the JPEGs altogether before they get put into the PDF, compared
to the size of the PDF?

Matt

On 2/8/06, Nicholas Watmough <nickw at deakin.edu.au> wrote:
>
> Hi,
>
> I am trying to scan a number of pages, then write the output to a PDF
> using reportlab. The size of the PDFs generated is much larger than
> would seem necessary, but I'm not sure why. I've tried to reduce the
> file size, but it doesn't seem to work.
>
> I am using the Python TWAIN module to scan the images, which passes the
> images in BMP format. I use the Python Image Library to open the BMP,
> and write the PIL object to the PDF using drawInlineImage(). I tried
> changing to using drawImage(), which required me to wrap the image in an
> ImageReader object, but this did not decrease the output PDF file size.
>
> The produced PDF file size was approx 2MB.
>
> I tried to reduce this by using JPEGs. So I saved my BMPs into JPEGs
> (using an StringIO class), then reopened the JPEGs using the PIL, and
> wrote the PIL object to the PDF using drawInlineImage().
>
> The resulting PDF file size was 7.8MB.
>
> When I turned on page compression, the file size was reduced to 6.8MB.
>
> The PDF I am generating only has 11 pages (11 images).
>
> When I try doing the same thing using a commercial tool (Omnipage), to
> do the scanning and production of the image-only PDF, the resultant file
> size is 0.4MB.
>
> While I realise that an open source tool may not be able to achieve the
> same reduction level as a commercial tool, the file sizes I am getting
> using Python seem too large. Particularly as I am getting larger output
> for JPEGs than I am for BMPs.
>
> Does anyone know how I can reduce the file size of my produced PDFs? I
> suspect I may be doing something wrong with the JPEGs, but not really
> sure.
>
> Nick
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