January 18th, 2006 • 2:47 pm
This is something that has been puzzling me for a long time. It has been a problem in Mac OS X for as long as I can remember, and appears to be associated to the underlying text rendering technology used by the system.
In a nutshell, the problem is the following: In certain circumstances, with certain fonts at certain font sizes, text in italics looks smaller (or bigger) than text in roman characters.
Here’s an example that everyone should be able to reproduce. In Safari, set your standard font size to 16 pt (in Safari’s preferences, under “Appearance”). Then load this page.
It’s a page that uses a Times font for the body text and, as far as I can tell, with the standard font size set to 16 pt in Safari’s preferences, the font size for the text of this page as rendered in Safari is Times New Roman 14 pt.
Now scroll down to the paragraph starting with “The straw man is being set up here…,” and check out the 10th line in that paragraph, which should be the line starting with “example), and what it means…” Note the word in italics (“means”). Doesn’t it look smaller than the rest of the text to you? It certainly does on my machine:
If I blow this up, you can see quite clearly that the characters in italics are one pixel shorter than the other characters:
Normally, the top edge of the text should be aligned with the bars in the roman “t” and “f” characters that enclose the word in italics, as it is when the text is in roman characters:
So what’s going on here? I tried a few things in order to better circumscribe the problem… and I noted the following.
The problem doesn’t just affect Safari. The same text is also rendered improperly in Camino, for example. And if I copy the text and paste it into an empty TextEdit document and make sure it’s in Times New Roman 14 pt, I get the same problem in the same location in TextEdit.
The problem only affects text with a font size of 14 pt. If I make the text bigger or smaller, the problem disappears.
The problem only seems to affect a small number of fonts. I was able to reproduce it with Times New Roman and Times, but not with several other serif fonts I have on my machine. Interestingly, I was able to reproduce a similar problem with the Garamond font that I have on my machine and seems to have come with Microsoft Office, but the actual problem is the opposite. This time the text in italics is too big:
Since the problem occurs in a variety of applications, I have to suspect a problem with the underlying font rendering technology used by Mac OS X. But I find it surprising that this problem has been around for years and that no one at Apple appears to have noticed it, or done whatever is necessary to fix it. The Times New Roman and Garamond fonts I have might be Microsoft TrueType fonts, but the only Times font that I have on my system at this point is the “.dfont” font file that’s located in the “Fonts” folder inside the system’s own library folder. And I am able to reproduce the problem with that font as well, so it’s not just a problem with a couple of third-party fonts.
It’s hard to research this particular problem on the Web, because the key words used to describe it are so common (small, font, text, italics, etc.). So I haven’t found anything about this particular problem anywhere.