jiho escribió:

If I understand you well this means that you export the whole  
Inkscape document to PNG and then transform it to PDF with OpenOffice  
Impress (you could do the same with the Gimp or ImageMagick's convert  
actually). If this is what you do, you could keep it in PNG instead  
of turning it to a PDF, it won't change a thing.
PDF is a vector based format and PNG is a raster format:
http://en.wikipedia.org/wiki/Vector_Graphics
http://en.wikipedia.org/wiki/Raster_Graphics
The advantage of exporting to PDF from Inkscape's SVG (which is also  
a vector format) is that you keep the vector information (i.e. when  
you zoom in, the lines stay sharp). If you export the SVG to a raster  
format (PNG here), no matter in which format you convert the PNG  
afterwards, you won't get the vector information back, you will still  
end up with just a bunch of pixels.
In fact, the raster/vector difference is complicated by the fact that  
you can include some raster images in a vector based format. For  
example you can include some raster images in an Inkscape document.  
And what you do in your PDF conversion is exactly that also: you just  
include a raster image (a bunch of pixels) in a vector document (the  
PDF), but that does not turn it into vector in any way.
I hope this helps. Maybe the FAQ in Inkscape's wiki need to be  
expanded a bit about this:
http://wiki.inkscape.org/wiki/index.php/FAQ#What_is_vector_graphics.3F

Cheers,

JiHO
Yes, well not exactly... I'm conscious of the differences of Raster and Vector graphics. I only export those elements I want to fine tune. If anyone uses Linux, then using Scribus is another possibility, which means a better PDF exporter than that of Inkscape's native one, which then means no need for GIMP, and direct manipulation of the SVG within Scribus itself, as it supports the format (I ignore if inkscape specifics are lost, like blur effects and the like) when manipulating directly the SVG within scribus. Another way to do this, is to export image portions to a separate raster format
in a higher DPI modify as needed in GIMP, then export or save-as another SVG the text elements, and compose the final document in Scribus (much better way than using OO.o as intermediary) then fine-tune the PDF options within Scribus. I did not mention this earlier, as I did not know if the OP used Windows or Linux, as Scribus is only available (AFAIK) to Linux and POSIX Unices.