I’ve scanned in 39 pages of invoices (nothing fancy, just ordinary documentation) and made a .pdf file. When I look at its properties it is about 22Mb in size.
I’ve just downloaded the Barclays interim finance report (similar documentation in terms of amount of text, etc; if anything more "busy"). This is 93 pages long, but only 3.2Mb. Why is my document so large (in terms of Mb) whilst being containing only about 40% of the number of pages?
I’d like to Know because I am thinking of composing a ,pdf file to send to other people via e-Mail and fear it may be too large.
PDF is very good at shrinking text and formats, much less good at shrinking images - your scans are (presumably) jpg images and they don't get squashed very much by a pdf creator.
You need to reduce the size of each scanned image - either by rescanning at a lower resolution, or using something like Picasa or Photoshop to produce smaller image files.
A lot can depend at what resolution you scanned your invoices, your scanner software should have some defaults such as 'document', 'photo' etc. In general documents need a lower resolution than photos and therefore create smaller pdfs
My scanner has the options "document to pdf" and "image to pdf". I used document to pdf. I have no other options. It seems that each page is about half a meg, which seems excessive.
I'll have a play around with the other suggestions you've kindly provided.