css - Is clockwise or counter-clockwise rotated text easier to read?

When rotating text with css, should it be rotated clockwise or counter-clockwise? Is one more readable than the other?

Counter Clockwise:     —    Clockwise:

Answer

I believe neither is “easier” to read in general, and I would instead try to make it a country-dependent setting that mimics the common book spine orientation, either in the visitor’s country or in the web site’s country.

In Wikipedia’s book entry, the spine tilting section says the following:

In the United States, the Commonwealth and in Scandinavia, titles are usually written top-to-bottom on the spine. This means that when the book is placed on a table with the front cover upwards, the title is correctly oriented left-to-right on the spine. This practice is reflected in the industry standards ANSI/NISO Z39.41 and ISO 6357.

In most of continental Europe, titles are conventionally printed bottom-to-top on the spine so, when the books are placed vertically on shelves, the title can be read by tilting the head to the left.

My personal preference is counterclockwise rotation, which is consistent with the above since I live in France. A quick look at the ~500 books in my library confirms this: books in French, Spanish or German use CCW whereas books in English (British and American) use CW.

Edit: it appears that book spine orientation does not necessarily reflect the ease with which it can be read when the book is standing on a shelf. My further understanding is that European books would use CCW because the spine can be read easily when standing, and American books would use CW because the spine can be read when standing (not necessarily with ease) and they can be read easily when lying flat. I don’t have much to back up this theory, though.