One simple method is reducing the thickness of the paper. Some publishers are turning to subtly thinner paper. There are limits to this: the most lightweight paper may be less durable. And for certain types of books, including art books, there’s a preference for heavier paper.

Yet between these extremes, most readers are unlikely to notice the difference.

Nor would most readers notice the design tweaks that allow more text to fit onto each page – as long as designers ensure that the text remains easy to read.

The publisher HarperCollins has experimented with compact typefaces, external that require less ink and paper. This has resulted in savings of hundreds of millions of pages.

A leader in this field is Sustainable Typesetting, a project of the design and typesetting company 2K/DENMARK. One of the company’s focus areas is complex typesetting for long texts, including Bibles.

Andreas Stobberup, project lead at 2K/DENMARK, says that Sustainable Typesetting can achieve page count reductions of up to 50%, although he recommends less dramatic changes for novels.

While it’s common to simply increase the point size to make text easier to read, Mr Stobberup says that readability is actually determined by x-height. The x-height is the height of most lowercase letters in the Latin alphabet, and makes up nearly all of the printed marks on a page.

The x-height can be increased without enlarging all of the text. For many designers, increasing the x-height is key to increasing legibility .

One of the typefaces 2K/DENMARK has designed is called Sustainable Serif. This has a larger x-height than, for instance, the popular typeface Garamond.

Compared to Sustainable Serif at 12 point size, “for Garamond to have the same size of the letter, it has to be scaled up to 15.2 point size,” Mr Stobberup says.

Typefaces like Garamond also have thinner lines and strokes, which can fade on the page as point size is reduced. Sustainable Serif has thicker strokes.