Just saw the Garamond item (http://flowingdata.com/2010/01/29/save-pens-use-garamond-font) today.
I wrote some Perl script to read a BMP file of three fonts, all set to 24 point and displayed on a screen. The size of the BMP was identical in all three cases, so the position of the text within the BMP field made no difference as long as it did not impinge on the border of the image. The script reads the BMP file and counts the black pixels/white pixels and expresses the number of black pixels as a percentage of all pixels (black + white).
I used the following text:
abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
0123456789
Here are the results in descending order of "ink usage."
Font: Arial
Percent of black = 11.975%
Font: TimesRoman
Percent of black = 8.360%
Font: Garamond
Percent of black = 6.062%
Faster/cheaper than pens.
