Approach to reduce the weight of an STP

Answer:
A SDS that you sent was scanned by you but didn't come directly from the supplier. Therefore the file can no longer be reduced because the reduction can be done only in the moment of scan.

However, if you receive SDS directly from the manufacturer in electronic format, you can eventually reduce their size by using a tool for creating PDF (Primopdf example). The manipulation is simple:
- Open the SDS with the corresponding application,
- Select "File / Print"
- Selected Primopdf in the list of printers
- Press the button "Print"
- Primopdf inventes you to choose where you want to store your new file
- Press OK and you get your PDF