Inkscape 0.48.5 r10040 win32
Inkscape 0.91pre3 r13670 win64
Windows 7 x64 SP1
NOTE: This happens the same way in both versions of Inkscape that I have listed above both with 'fresh' profiles created by Inkscape on the first run.
Steps to reproduce:
1. First, download the following PDF from Sylvania's website: https://assets.sylvania.com/assets/Documents/RETRO053.64ed2042-64e7-4e16-9150-ffda82e7bd6d.pdf
2. Load the PDF in whatever PDF viewer you have installed on your system and take a look at the bottom right of page 2 at the 'lightbulb' logo for Sylvania and notice how the bulb looks with it's gradients.
3. Now, start Inkscape and go to 'File > Open' and select the PDF you downloaded above.
4. Select the following settings for the 'import': Page 2; Precision 246.0; 'Import text as text; and the 'Replace PDF fonts' & 'Embed images' boxes checked.
5. Now hit the 'OK' button to open the PDF file in Inkscape.
6. Now, wait for a few minutes for Inkscape to open the PDF file.
7. Once the file is opened, zoom in on the lightbulb logo area and notice it didn't import correctly at all. (images attached showing how it looks in 0.48.5 and 0.91pre3 on my system).
So, I recently saw some Sylvania bulbs at a local store and noticed the gradient on the lightbulb part of the logo. I then decided to look for an official PDF online from them to try to see if the logo would load correctly in Inkscape for fun and to see if there was any bugs doing so. It seems that my hunch was correct that Inkscape would have a problem with it. :( Loading the linked above PDF file in Firefox 35 (via built in PDF viewer) and via SumatraPDF 2.5.2 (after being saved to my PC), the lightbulb gets rendered correctly (and quickly I might add). So, Inkscape just happens to have a problem on the import end it seems.
AFAIU to be expected - the bulb uses a feature which doesn't exist in SVG 1.1 (and is thus approximated on import). Import of gradient meshes from PDF in trunk or 0.91pre3 as Inkscape's experimental SVG gradient-mesh feature hasn't been implemented yet.
For a better result (based on current available features in trunk and 0.91): use e.g. 125 as precision for gradient meshes on import, zoom in to the logo and turn off anti-aliasing in the document properties: without the anti-aliasing effect at adjacent edges of the imported mesh patches it looks quite ok (yes, the anti-alias setting will affect other parts of the document, but that's part of the refinement needed for bug #170356 (to allow to apply the setting to a selection instead of the full document)).