Anthony Haynes writes: The headline above this post is all in upper case. That probably helps to make a bold initial impression.
But it isn’t actually very readable.
To see why I say this, try a simple mental experiment: imagine the headline in sentence case. The first letter, T, will, as the first letter in the sentence, take upper case. (Arguably, you could do the same with the first letter of the sub-title, t/T.) The rest will be in lower case.
As a result, the headline will be more readable than in its current form.
Why? Because, when we read, we don’t normally read every letter (one reason typographic errors can be difficult to spot). Typically, we decode words by looking at their overall visual morphology.
Two of the main cues for this are (in non-technical language) tails and heads. By tails, I mean those parts of letters that go below the line. In the above headline, lower case g, p, and y have tails.
Heads are the upper bits of tall letters. For example, f, h, l, and t.
You can see the problem with upper case: the letters are all the same height. Thus continuous upper case makes our apprehension of words less direct.
It’s very common to see that, in wanting to give headings (or some other piece of text) emphasis. presenters resort to UPPER CASE.
This is understandable, but self-defeating.