[sax]

Now, What really needs to be done is to compare "Ink Efficiency" with "Legibility". I wonder if there are other factors which can be used to determine whether one font is "better" than another?

BTW, the ink efficiency is better determined using weighted average of distribution of letter frequency in language use over the alphabet and should be trivially determinable by parsing font files.

Sounds like an a valuable mini exploration project suitable for print media.

[EDIT]. Additionally, for display optimizations you need to maximize "Legibility", "Font Size" at various contrast ratios on screen. It would be interesting to be able to quantify an optimal "Font Face" and "Font Size" for various contrast ratios (screen power consumption) for mobile displays.

[ethan]

>I wonder if there are other factors which can be used to determine whether one font is "better" than another?

I can't find them, but a lot of studies were done on type legibility when Hoefler Frere-Jones redesigned the typeface for the US interstate signage system. They made a lot of interesting findings, such as a word with an inital cap followed by lowercase was more legible than all caps or all lowercase; or that lowercase 'L's are more easily read when they have a small hook at the bottom, as opposed to jut being a straight line.

[tesseract]

I don't think it was H&FJ. http://clearviewhwy.com/, http://www.meekerdesigns.com/

[wtallis]

It seems to me that calling it "ink efficiency" is framing it in a way that ignores readability and legibility. The more common term for this is "font weight", which we already knew was independent of the pitch (size). It shouldn't be a surprise to anyone that the more generally readable typefaces are in the middle of the group.

[sax]

Yep, based on intuition it would definitely seems like fonts with similar font weights (assuming the same font size), would offer similar legibility. The real question is, given a choice of font and the requirement of printing a novel or HN front-page on a mobile device, how do you quantify the trade-offs between them, so that one can say, this saves 'X' amount of ink or power for the same legibility?