Why an EPUB looks wrong when you just print it

You have an EPUB. You want it on paper. The obvious move is to open it in whatever app you read in and hit print. The result is almost always disappointing in the same handful of ways.

What you get instead of a book

Enormous type. Reading apps print what is on screen, and what is on screen is sized for reading at arm’s length on a backlit display. Transferred to A4 it comes out at something like 16 or 18pt, which on paper reads as a large-print edition nobody asked for. A 300-page novel becomes 600 pages.

Margins from the screen, not the page. The app was leaving room for your thumbs. A printer needs room for a binding, or at least room that does not look like a mistake. These are different amounts in different places, and the app has no idea it is now making a physical object.

No page numbers, or the wrong ones. An EPUB has no pages, so the app either prints nothing or prints its own invented “location” numbers, which mean nothing once the file is on paper and correspond to nothing anybody else would see.

A table of contents that does not work. If it prints at all, it is a list of chapter names with no page numbers next to them, because at the moment it was written there were no pages to number.

Chapters starting halfway down a page. Reading apps flow continuously by design; that is the whole point of a reflowable format. Paper wants a chapter to begin at the top of a fresh sheet.

Why this is not the app’s fault

None of that is a bug. It is the format doing exactly what it was designed to do.

An EPUB is a zip full of HTML with no page size, no page count and no fixed line breaks. The reading app invents all of that, fresh, every time you open the book, from your screen and your chosen font. That is why the same novel shows 312 pages on your phone and 190 on a tablet: neither number is in the file, because there is nothing in the file to count.

When you print from that app, you are asking it to commit its on-screen guesses to paper. It obliges, because that is the only thing it knows how to do.

What converting properly does differently

The conversion has to make the same decisions the app was making, but for paper instead of for a screen, and it lets you choose:

• A real page size. A4 or Letter, so the type is set for a sheet of paper rather than scaled onto one afterwards.
• A real type size. 11pt is a book. You pick it, once, up front.
• Real page numbers, and a contents page whose numbers point at them.
• Chapters starting on fresh pages, because paper is not a scroll.
• Justified text with a straight right edge, which is what a printed book looks like and what a reflowing screen usually cannot manage.
• Running heads, the chapter title along the top, so you know where you are in a stack of loose sheets.

None of this is clever. It is just the set of decisions that has to be made when something stops being able to reflow, made deliberately rather than inherited from a screen.

The one thing to check before printing

Set your print dialog to Actual size or 100%, not “Fit to page”. Printers cannot print to the very edge of a sheet, and “fit to page” shrinks everything by a few per cent to stay inside that border, which quietly undoes the margins and type size you just chose. It is the single most common reason a carefully made PDF prints looking slightly off.

Then print two pages before you print two hundred.