Save as PDF doesn't (re)compress raster images like Print to pdf may do

Summary:

Inkscape 1.2-beta's has a new multi-page feature. However, File > "Save a Copy" to PDF outputs a file size that is about 10x larger compared to the combined printing out of each PDF page individually.

Steps to reproduce:

Method 1: Manual PDF creation

• Make a SVG with a page worth of content in a layer. Include raster images so that a PDF page filesize is large enough to use as a baseline.
• Repeat firs step 2 more times, so that 3 layers are created in total. Each layer will represent 1 printable pag4e
• Hide all but one layer and print page to PDF
• Repeat for other layers
• You should have 3 PDF files, each representing 1 page of content
• If wanted, a tool can be used to concatenate the PDF's to one PDF (e.g. pdfunite page1.pdf page2.pdf page3.pdf OUTPUT.pdf)

Method: Inkscape 1.2-beta multi-page Save a Copy method

• Duplicate the above SVG document
• Using Page tool, create 3 pages in this new document
• Drag layer 2 content to page 2
• Drag layer 3 content to page 3
• Now page 1, 2 and 3 are set up to be turned into PDF. File > Print cannot be used since Inkscape doesn't know how to correlate an Inkscape "page" and a print "page"
• File > Save a Copy and save to PDF

What happened?

• In my test using the first method, the 3 PDF files took up 5MB of diskspace
• In my test using the second method, the Save a Copy PDF took up 50MB of diskspace

What should have happened?

Similar PDFs with the same content and pages should be similar in overall filesize. I tried to zip the the larger 50MB PDF to see if it would compress down to 5MB. The filesize stayed around 50MB. ...

Sample attachments:

None

Version info

• Inkscape 1.2-beta (1b65182, 2022-04-05)
• Ubuntu Fossa Linux
• Inkscape-1b65182-x86_64.AppImage