Printer’s Glossary

Essential vocabulary about print files and book layout.

Files – Layout




There are many technical terms in the world of printing, which are all important to master in order to be able to successfully complete a project.

In this section you will find the essential vocabulary regarding the preparation of print files and the layout of a book.

Adobe InDesign⮯
CIELAB colour space⮯


Front cover (C1)⮯
Back cover (C4)⮯










Solid colours⮯

Spread with bleed⮯
Text alignment (justification)⮯

Adobe InDesign

Industry-leading desktop publishing (DTP) software. It was designed for the layout of books, magazines, newspapers and all types of print.


Additional printed material that is added on the outside of the finished format to ensure the book has the best possible finish when cut. There is a need for bleed when there are elements (image, photo, colour background, line) close to the edge of the finished format. This is the case for virtually all book covers. If you do not have any bleed in your book layout, make sure there are no graphic or text elements within 0.125” (5mm) of the edge of the page.

See our how-to video for more details.

book layout bleed

CIELAB colour space

Colour space used since 1976 to characterize a colour according to three parameters:

  • L represents perceptual lightness,
  • a represents colour on one axis from green to red
  • and b on another axis from blue to yellow.

Also called L*a*b, it is the colour representation system most consistent with the perception of the human eye.

Source: LinshangTech


A section usually included at the end of a book, which provides the reader with information about the book’s composition and printing: the fonts used, the type of paper, the name of the printer and the publisher. This is a tradition that has become a bit lost over time, but it nevertheless gives the book its full glory.

We will not take the initiative of including a completed colophon ourselves in the books we print. But if you want one, please contact us so we can provide you with the required information paper stock specifications.


Front cover (C1)

Also called C1, the front cover is the cover page of the book, which includes the title and author’s name.

Back cover (C4)

Also called C4, the back cover is the page at the back of the book that usually contains the book blurb and section about the author.


An encapsulated postscript file (EPS) is a type of file that can be encapsulated in another file, such as a native Adobe InDesign file. Created by Adobe, it is an open format that makes it possible to share images made up of vector or bitmap objects while retaining all their vector qualities. It is very popular with professional graphic designers, mainly with Illustrator.


The page number which is usually indicated at the bottom of the page of the book, or on the outer side of the page. Traditionally, folios are not included on blank pages, nor on the title page, dedication, epigraph or copyright pages. In some cases, folios are also excluded from chapter and section heading pages. Some introductory pages may be in Roman numerals such as the table of contents, the list of tables and illustrations, the list of abbreviations and acronyms, the preface, the dedication, the epigraph, the acknowledgments, the foreword and the disclaimer. From the introduction onwards, Arabic numerals are used, starting over at number 1. Annexed pages (annexes, appendices, bibliography, index and/or glossary) are also typically in Arabic numerals.


The monochrome colour chart allows the user to evaluate the levels of gray (in an image). The grayscale range is used to reproduce black and white images, ranging from the lightest gray to 100% black.


The International Standard Book Number is an identification number that you can obtain free of charge and that is required for the sale and distribution of a publication in Canada. The ISBN is used by booksellers, publishers and librarians. See our article on ISBN for more information.


Template that draws the boundaries within which the text will be placed for all inside pages of a book, except the table of contents, credits, bibliography and index pages which have different layouts for practical reasons. Read our article on the layout template here.


Last line of a paragraph on the first line of a page.


A PDF, short for Portable Document Format, is a file format invented by Adobe in 1992. It preserves the layout elements of a document such as text, fonts and others regardless of the software or operating system used to print or view it. PDF is the file format used by all printers.


Number of dots per unit length that an image can have on a screen or paper. It is commonly measured in dots per inch (dpi) and provides information on the quality of the images. The ideal resolution for printed images is 300 dpi. At Rapido, images under 200 dpi are flagged and only printed with the express authorization of the client. It is important not to confuse the resolution (of an image) with the definition (of a screen) which expresses the number of pixels displayed on a screen (for example 1280 x 1024).

Image Resolution (DPI)


RGB, short for “Red Green Blue,” is a colour model that works by additive synthesis. It allows a screen to display any colour, by combining the three primary colours using a colour grid. RGB files are not used for printing, but are converted at the time of their export in PDF to CMYK (Cyan, Magenta, Yellow, Black) in order to obtain a more faithful rendering of colours.

Difference between RGB and CMYK


The process by which an author publishes a book at his own expense. Before the creation of the first publishing houses in the mid-19th century, this was the only way to publish a book. Today there are professional self-publishing solutions to support authors in the publication of their manuscript, such as BouquinBec in Quebec.

Solid colours

Term used in printing for all graphic elements that are neither text nor an image without gradients, whether they are gray or in colour.

The term Ben Day was also used in the past, named after the illustrator Benjamin Day who developed this screen printing technique (with lines of dots). This was a considerable advance in colour reproduction, which until the end of the 19th century was only achieved through the use of direct ink tints.

With the Ben Day technique, one can for example compose an orange red with a yellow halftone of 90% and a magenta halftone of 30%.
Solid colours

Spread with bleed

Spreads are one of the more technical elements of a book’s layout, unless you are doing a paperback or spiral binding.

Avoid at all costs: make sure there are no faces or key graphic elements in the centre of the spread, otherwise there’s a risk that these will get lost in the fold of the book (see example below).
Avoid if possible: keep in mind that diagonal lines on this type of image are rather unforgiving. Ask us for a proof copy, then adjust your bleed.
We recommend an overlay between the left and right pages of 4mm inside each page for softcover binding and 5mm for hardcover binding. You can always reach out to us if you need assistance with this.
Spread with bleed (print file/mistake to avoid)
Print file (mistake to avoid)
Spread with bleed (printed result/mistake to avoid)
Printed result (mistake to avoid)

Text alignment (justification)

In typography, text alignement refers to the longest width a line of text can have inside a particular book. The dimension of this width can be calculated according to the rules explained in our article on the layout template.


First line of a paragraph on the last line of a page.

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