I have imported a 75 page pdf into Corel 14 as curves as I didn't want any font issues, I had to add some backgrounds etc to the document.
As this document is going to be emailed to a lot of people I need the file under 20 mb but when I save it as a pdf it is 120mb.
Is there any way I can vastly reduce the file size without losing quality of the document.
What application was used to create the 75 page PDF? CorelDRAW or a rival graphics or page layout application? Obviously the best thing to do would be editing the original 75 page file, not a PDF exported from it. PDF files are not really meant for further editing after being created. Various applications (including CorelDRAW) introduce a whole lot of messy trash into PDFs to make the layout appearance look consistent and accurate. One exception is PDF files output from Adobe Illustrator saved with Adobe Illustrator editing capability left intact, but that is essentially an AI file twinned with a PDF.
Aside from all the vector trash common to imported PDFs any pixel based images (such as photos) will likely have had a level of lossy image compression applied to them. Opening a PDF in an application like CorelDRAW and saving it again will apply yet another level of lossy compression to an image that has already been compressed at least once before. Basically levels of generation loss are being cooked into the image. It's like taking a photograph, putting it through a copier and then making a copy of that copy.