Bleeds can sometimes start difficult questions. We are here to make it easy.
Not every book requires bleeds, but when they are needed, they are very important.
Bleeds are an extra area beyond the trim area of the book format, that extends over the cutting lines.
This extra area is used for the sole purpose that there will not be white boarders around the edge of the pages that are supposed to be covered fully with colours, graphics or other elements that extend to the edge of the page.
If a page has a full blue background, then the extra few millimetres of bleeds ensures that when the book is on the cutting block and is being trimmed to format, the blue fully covers the whole page.
In case of the margin of error on the cutting block, without bleeds, half a millimetre shift error outward means there will be half a millimetre of white boarders around what should be a page covered fully in blue.
Bleeds should be 5mm but can be a minimum 3mm. This is for all books that have pages that have fully coloured backgrounds on pages, photographs extending to the page edge, boarders, or other elements that extend to the pages edge. You can even add bleeds to a text novel if you really want to, although it wouldn’t be necessary at all.
For covers, bleeds are always required unless it has a white background without any graphics extending to the edge. 5mm for softcovers and 18mm for hardcovers. The reason it is 18mm for hardcovers is due to the fact that the printed cover paper is glued to the hardcover board. The much larger bleed area is for the wrapping of the printed cover paper over the cover board when gluing.
In the image below, you can see the bleed area for a hardcover book. It has 18mm and contains no important elements, as the printed cover paper will be wrapped and glued over the board’s edges of the hardcover. The most outer drawn lines are where the wrapping will start over the board. Pick up a hardcover if you have one at hand and look on the inside cover page and you’ll see where the pasted cover has been wrapped around!
If it were a book page, with 5mm bleeds, the most outer lines would be the trim lines, where the pages will be cut to format on the cutting block. It will ensure the background colour will extend right to the edge of the page. Otherwise, there could be white borders around the edges if the cutting knife shifts a touch beyond the computer registered format.
It is necessary to not have any important text, graphics, or elements in the bleed area that you do not want to be cut off or hidden.
If you ever have any questions about bleeds or anything else for that matter, you can always get in touch with one of our experts.
Enjoy!
Author
Benjamin Lewis
One of the directors at Books Line and he loves writing. He spent his education writing scientific publications at university before he set off into the world of printing. He also enjoys reading, environmental science & listening to podcasts whenever he can. Currently waiting to publish his own research on sustainable protein – look out for it!
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