A Quick Guide to Popular Printing Terms

As with all specialist professions, the world of printing is home to a variety of specific terms and expressions that are alien to those not working in or involved with the industry.

If you’re working on a project that requires professional printing services or you need to use a printer on a regular basis to help produce high quality products for your company, understanding these terms can make the process a lot easier. Below is just a few examples of the keywords you may come across.

Bleed

This is where the background or images extend (usually by 3mm) further than the crop marks. This makes trimming easier as often large flat sheets are printed then folded several times before being trimmed.

See our guide on preparing artwork with print bleed

CMYK (4 colour process)

CMYK refers to the four inks used in commercial colour printing. These colours are Cyan, Magenta, Yellow and Black. Used in combination they can simulate a wide range of colours.

Crop marks (Trim marks)

These are thin lines which indicate where the paper is to be trimmed. They will appear on each of the colour printing plates and are usually placed in the corners of your document.

DPI

This stands for Dots Per Inch. To print a photographic image, it needs be printed using very fine dots. For a magazine, brochure or leaflet they will be printed at 300dpi, so there will be 300 dots per inch.

EPS

EPS stands for Encapsulated PostScript. PostScript was originally designed only for sending to a printer. It is now used by many vector based programs like Adobe Illustrator for creating scalable artwork.

GSM

Grams per square metre is the standard measurement of weight for paper. A thin paper, such as that used for a letterhead or compliment slip would be 80gsm, a booklet or leaflet would be printed on a 115gsm to 135gsm and a flyer printed on 170gsm. A postcard or greetings card would be printed on a heavy stock of around 260gsm to 300gsm and business cards will often be printed on a 400gsm card.

Overprint

As the name suggests, this is when a colour overprints another. Generally black text will be set to overprint so that it avoids any white gaps appearing around it. It is always worth checking if colour is set to overprint either in your DTP software or in Adobe Acrobat. This can be done by selecting the option in ‘Output Preview’.

RIP

A RIP, or Raster Image Processor, is a system used in litho printing that enhances a printer driver’s capabilities to process postscript files. It is usually a combination of software and hardware that speeds up the processing and improves image quality.

Separations

In order for them to be printed on a commercial printing press, the majority of print jobs will need to be output as separations, ie as seperate colour plates. These will either be spot colours, 4 process colours or a combination of colours and finishes. Many top offset lithographic printing presses such as the Heidelberg Speedmaster can print up to 10 colours in one print run, this allows for additional spot colours and spot varnishing to be used. Separations are created as part of the printing process and although it is good practice to check separations on screen it is not necessary for you to supply artwork in this form.

Swatch book

A swatch book is small samples of paper or ink colours. The Pantone Matching System (PMS) for example, is probably the most well know range of colour swatches. They include a range of spot, metallic and process colour reference books.

TIF

A TIF, also referred to as TIFF (Tagged Image File Format), is a file format used to save images, similar to JPEG. Images are stored in a bitmap form and can also be saved in a compressed format (LZW) that is lossless, so image quality is preserved. Software such as Adobe Photoshop also supports layers as transparency in TIF files.

For a more comprehensive list of Printing Terms see our guide