Myths are powerful factors in our lives. They can blind us from the truth. One such myth I've discussed often is the idea that monospaced fonts demand more space between sentences than proportional fonts. Any rational analysis of the geometry will completely contradict this myth, as does the history of what actually happened when typewriters were introduced.
But myths are so powerful that otherwise rational human beings will literally lie to themselves to hang on to the myth. I came across one such example today on a blog called "Show The Data". It's a blog about the visual display of information, and they created a visual in service of the monospaced font myth. It's a striking visual and at a glance forms a compelling argument for that viewpoint, until you begin to notice just how hard they had to work to distort the data, rather than showing it.
If you like the myth and you like the visualization then at this point you're done and move on. And you'll never notice that you've just been fed a huge lie in the form of visual distortion.
Look again. The pink square between the two “i”s is not really between them, it's on top of them. It completely overlaps the serifs on both letters, and touches the stem of the letters. This essentially doubles the size that this pink rectangle should actually be. Now look at the pink rectangle between the period and “Maria”. It does not touch the period, and it does not touch the “M” (to say nothing of overlapping the serifs). And now compare that pink rectangle to the other pink rectangle in the second line. This pink rectangle does overlap the serifs of the “M”, and touches the stem. It not only touches the period, it completely overlaps it, and covers whitespace to the left of the period, almost touching the “g”. So what happens if we fix these problems in the image, and consistently mark the spaces? I adjusted the boxes so they all touched adjacent serifs without overlapping them. I chose to cover both periods entirely because in my opinion periods don't have enough weight to take up real visual space, so including the period in the spacing, as he did with the proportional font, is the way to go. This is what we get:
That's a striking difference from the first graph. The argument looks ridiculous now. It's even worse actually because he totally cheats on the space between the period and the M in the proportional font. The space between “Maria” and “was” is nine pixels, but he has twelve pixels between the period and the "M". He probably chose one of those odd fonts that misguidedly adds space to the right side of the period regardless of how and where it is used. This means that he has exaggerated his idea of sufficient even more than I've shown here.
But you might have noticed something else that's odd. He compares a letter space in the first line with a word space in the second. He sort of covers this issue in the blog text, where he talks about the problem you can have with letter spacing and how it can confuse word and sentence parsing. This actually plays to my advantage here, as it makes the comparison ridiculous, where if I were comparing word and sentence spacing between these two lines they would actually both be very close to double the size in both fonts, as a period and space is twice as big as a space in all monospaced fonts and very close to that in most proportional fonts.
Still, if he was simply trying to make a point about letter spacing issues in monospaced fonts, why did he, an alleged expert in the portrayal of visual information, have to cheat so hard to make that point?
I haven't talked to the writer, but I'm going to guess that he did not intend to commit a fraud upon his audience. Most likely he set out to demonstrate a point, and when it didn't work he fudged reality to fit the myth, rather than questioning the myth itself.
Because we're human beings. And that's how we roll.