Why is capitalized text difficult to read?
It is not known where the fashion for writing text in capital letters came from, but the fact remains - the use of capital letters surrounds us everywhere. If you write the text in capital letters on the Internet, people will decide that you are screaming or will doubt your mental health. But most often, all capital letters annoy people, and the text written in this way is very difficult to quickly read.
People use this technique, wanting to emphasize what was said, believing that such a text will attract more attention. But in fact, the message typed in capital letters does not emphasize what was said, but rather is lost in comparison with the usual set. The reason for this phenomenon is the lack of contrast between the forms of the letters of the text typed in capital letters.
Uppercase text significantly reduces the contrast of the shape of each word. In fact, the shape of any capitalized word, regardless of the font selected, with or without serifs, is always a rectangle. As a result, capitalized words have one adjacent edge of letters from above and below, which leads to a decrease in the contrast of the form. Words, in which only the first letter is uppercase and others are not, have many edges located near the top and bottom, giving the word high contrast. The more non-adjacent edges a word has, the higher its contrast. Words typed in this way are much easier to read. And when your message is easier to read, then its meaning will be understood faster.
Nevertheless, the text typed in all capital letters is used not only on sites, but also in books, advertising, television, cinema and magazines. And so it is everywhere, because it seems to people that in this way they can emphasize the importance of what they are trying to say. But if you are trying to say something really important, your message will say it for you without additional tricks. And applying all capital letters will only make it worse.
In what cases is it permissible to use all capital letters? Such a set is good in situations not related to reading, for example in logos and acronyms. But if your message involves reading, using all uppercase letters, and thereby worsening the contrast of the text, negatively affects the result. You want your text to be read quickly and easily? That is why the Caps Lock key in most cases is harmful.
Along with exclamation marks in writing, which are used extremely rarely, it is important to use all capital letters in design very rarely, or not to use them at all.