There are two main ways to effect the file size of a scanned PDF. The main way would be to lower the scan resolution. For most black and white documents you should not need more then 100dpi to get a good quality PDF. If the file size is still to large, next to the PDF file type option should be a Set button. When you click Set, there will be radio buttons for PDF Compression. The default is standard, and if you change it to high, it will reduce the file size.
For pdf size,you can compress the pdf size if you want to reduce the size of the pdf files.
Here is the code to do it:
DocumentEncoder = DocumentEncoder.Group3Encoding
RasterEdgeImaging Document = new RasterEdgeDocumentg();
Image. DocumentCompression(@"C:\1.pdf", "C:\2.pdf", DocumentEncoder DocumentEncoder.Group3Encoding);
Actually, different PDF converter will create different PDF size. When I want to save word to PDF. I use formats converter can get a larger PDF file, but I get a smaller pdf file when I directly save Word to PDF with microsoft office PDF converting plug-in.
I'm looking forward someone can share good resource for reducing PDF size.