I have two issues that may be related.
All text, regardless of font, from PDF documents in Preview (version 3.0.8) appears in very low resolution, reminiscent of the days of 72-dpi jaggy fonts.
Italics in Times prints out in a bizarre twisted fashion (in all applications)
The affected system is a early-model G4 first with OS 10.4.7 and then 10.4.8.
Here's the Preview problem.
What you see above is
exactly how it looks on a high-resolution 23-Cinema display. By contrast, it looks very sharp and crisp in Acrobat 7. Bitmapped images are not affected. Printout is not affected. Acrobat is not affected.
Now for the Times problem
Times plain looks good. The italics always look bad (except perhaps the last few characters and numbers.)
The following steps were taken:
A full, automated Onyx 1.7.4 cleaning, which includes the deleting font caches.
FontBook was run to resolved duplicate fonts and to verfiy all fonts.
The system was upgraded to 10.4.8 from 10.4.7 using the combo updater.