Compression techniques

[heretohelp]

~40 pages to < 4MB

Please get a scanner. Rent or borrow.
I have done 2 sets of scannings myself. One with Adobe on One Plus 7 Pro and one with Canon MG2500 scanner.
Jpegs from scanners compress better in terms of clarity post compression for 3 main reasons:

• The focus is consistent across the whole document
• Document is steady
• Document is non creasey because of pressure from the lid

All of the above with an added advantage of about 20% savings on images sizes(at ~150 DPI).

Camscanners in addition to Adobe software to "make it look like a scan" messes up the image. Try scanning a light travel stamp for instance. You will understand what I am talking about. The lighter stamp won't even show up on the Adobe scan.

Please conduct experiments with compression yourself before fully commiting to strategy. This is what worked for me.

My strategy :
- Split your documents with respect to priority and then original clarity.
- Priority documents should be scanned with highest DPI and must be least compressed.
- Clear documents can be highly compressed.

Scan with 200 DPI + "Add images" to word document + Basic/Strong compression should do the trick

Then use smallpdf.com to mix and match merge the pages. Smallpdf's merge tool in page mode is superb.
example :
There is a 2 page document. Page one is priority. You compress the document once with strong compression on smallpdf. Then you upload the original uncompressed pdf on the merge tool along with the compressed one. You select Page 1 of the original document and page 2 of the compressed document.

Pro tips:

1. On smallpdf.com you cannot compress a pdf twice. It says our algo cannot do that. BUT this doesn't apply to merged compressed pdfs. If you combine a bunch of compressed pdfs on smallpdf and then compress the merge result, it will bring down the size a bit more. This trick is pretty useful.
2. Scans with lowers DPI's might show a rainbow pattern. especially with striped documents like ICICI statements. Increase the DPI to 200.
3. Sometimes when you run out of ideas, try "compress image" in Microsoft word. Reduce the size of the images a tad using this option.
4. Microsoft Word's pdf export with "minimum size" is very aggressive but for certain type of documents, it might help. Mix and match again with smallpdf's merge tool.