There are some documents (or part of documents) that Poppler's pdftocairo rasterises on Windows instead of keeping them in a vector format. This causes a reduction in quality, colour mismatches and generally makes the print job larger.
Created attachment 677 [details]
lemon jelly sample
First sample, taken from here:
Created attachment 678 [details]
sunny farm invoice sample
Second sample, from here:
Note that both samples are rendered properly as vector images when using SumatraPDF, as well as pdftocairo's other backends and with pdftops.
More testing shows that the lemon jelly document not always are rasterized. Seems to be a dependent of which print driver is used.
Direct printing using "HP Laserjet 500 color MFP M570dn UPD PS" driver will make pdftocairo to only rasterize the fifth graphical symbol on first row. See attachment "minimal rasterized".
Direct printing using "HP Laserjet 500 color MFP M570 PCL6" driver, the results is 90% rasterized image. See attachment "90% rasterized". You can see in the scan the bounding box for the rasterization is almost the full graphics. Text around is vectorized.
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Not fully rasterized
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(In reply to comment #5)
> Direct printing using "HP Laserjet 500 color MFP M570dn UPD PS" driver will
> make pdftocairo to only rasterize the fifth graphical symbol on first row. See
> attachment "minimal rasterized".
As you can see here, the printer get confused of gradients and masking and renders those parts wrong. Very broken results.