Making blurry PDFs look better

February 10, 2008 7:55 PM

How can I make blurry PDFs (that use type 3 raster fonts) look better on screen?

A lot of PDFs created with older or poorly configure LaTeX setups use type 3 raster fonts, which look horrible in many screen viewers (they print fine). Now that I am switching to doing most of my reading of academic papers on my computer, I run into these files on a regular basis. My question is whether there is anything I can do either to my viewer (preferred: OS X Preview) or to the files themselves (via some ghostscript utilities or whatever) to make these look better.

They do look slightly better in Acrobat Reader 8, though still not as good as I'd like (compared to files involving type 1 fonts). I've read that they are even better in xpdf, but I will use that as a last resort. In general I would prefer not to have to use a different viewer for these. The page I linked above also has a magic ps2pdf command that hasn't worked for me (after turning the pdf into a ps), it just makes things worse. I don't know enough about ghostscript to know why.

My question is not about how to get good PDFs out of dvi or tex files. This, I already know far more about than I want to.

posted by advil to computers & internet (6 comments total)

Is the PDF viewer trying to anti-alias the text? I did a Google search for "disable anti aliasing os x preview" and came up with this, which you may want to keep an eye on.

It looks like CocoViewX will allow you to view PDFs and disable anti-aliasing.

Yet another trick you can try. Once again, these were all the top results from that above Google search.
posted by spiderskull at 9:26 PM on February 10, 2008

The problem isn't anti-aliasing, but poor rendering of type 3 fonts. Since they are raster fonts at a very high DPI, some processing would be needed to display them well on a low DPI screen, and for whatever reason, many viewers don't do it. Some pictures of the problem, so you can compare it to anti-aliasing, are here, though OS X's preview isn't quite that bad. Preview in 10.4 actually has a button for turning off anti-aliasing of fonts and it does not help.
posted by advil at 9:48 PM on February 10, 2008

in Acrobat Reader:

edit/prefs/page display -> uncheck "smooth text"

this worked for me in the past.
posted by drjimmy11 at 9:50 PM on February 10, 2008

I see. Is the text information still retained? Because if it is, then you can try to extract just the content without any of the rendering information. What does it look like when you use Adobe's online conversion tool?

I'm not familiar with PostScript or GS at all, so I can't help you there. Hopefully someone else here can. You may even want to try finding a specific forum with experts on this topic.
posted by spiderskull at 10:16 PM on February 10, 2008

If the problem is with a specific font (like Computer Modern, used in the linked example), is there a way to switch out the font for another? It would be a tedious pain in the butt to do so, but if it's the only option...
posted by caution live frogs at 6:14 AM on February 11, 2008

edit/prefs/page display -> uncheck "smooth text"

This doesn't change anything for me; it's possible I'm not going to get much better than what acrobat 8 is doing (which isn't bad, just still not as readable as I hoped).

Is the text information still retained? Because if it is, then you can try to extract just the content without any of the rendering information.

The text is retained, but most formulas and special characters are garbled. Actually the problem isn't bad enough to go to this extreme, I'm really trying to make it easier to read large/book-sized chunks of text on the screen like this (what prompted the question is that someone's dissertation that I need to read is formatted with type 3 computer modern.)

If the problem is with a specific font (like Computer Modern, used in the linked example), is there a way to switch out the font for another?

This is exactly what I was hoping someone would tell me :-). If there were even a solution just for computer modern (which has a good type 1 version) that would probably solve 90% of the cases. But I have no idea how to go about switching out fonts in a PDF or PS.
posted by advil at 10:36 AM on February 11, 2008