Data formats for digital pre-press

 

EPS (Encapsulated PostScript)

EPS is actually a page description language but is also used for describing images.

Purpose: A platform-independent printing format. EPC should not be used for screen presentation because images are not always displayed correctly.

Advantages: EPC has been a de facto standard within the graphic industry during the last fifteen years. It offers a very good printing quality on PS-printers. EPC is mostly used for storing vector information, which makes small files.

Disadvantages: There are sometimes problems when printing these files on printers that don’t support the Postscript format.

GIF (Grafic Interchange Format)

GIF is in most cases used for screen presentation. It can also be used as animated GIF.

Purpose: GIF should be used on the Internet if the image only requires up to 256 indexed colours. Images that have more than 256 colours should be saved as JPEG.

Advantages: Most image software can import and export GIF-files. The file format offers extremely small files. That gives fast download and display on the net.

Disadvantages: Maximum 256 colours can be stored in the file. That means that there is always a quality loss when you use it for photos.

JPEG (Joint Photographics Experts Group)

You can compress images very much and so it is mostly used for large photos. JPEG is the most common format on the Internet.

Advantages: The format offers a very good compression, especially for photos. The compression will reduce the file size by approximately 5 to 20 times.

Disadvantages: The format uses a lossy compression. This means that you will loose information every time you save the image. You should not use JPEG as a master copy of your images.

PDF (Portable Document Format)

PDF is produced by Adobe Acrobat and the format is based on PostScript (PS) format.

Purpose: A cross application and platform description and publishing format.

Advantages: Very good printing quality. A standard in desktop publishing. All information will be stored inside a PDF.

Disadvantages: Only limited options to edit a PDF-file.

TIFF (Tagged Image File Format)

TIFF is one of the most common formats.

Purpose: Platform independent format for photos etc. TIFF has become a de facto-standard for halftone images.

Advantages: Platform independent (DOC, PC, Mac and UNIX). The format is supported in almost every image and word processing software.

Disadvantages: Large images require large storage space. And so it takes a long time to download something from the Internet.

 

Source:www.formatguide.com

 

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Link the matching boxes

Read the boxes placed round Liza. Link the name of the data formats with the matching explanation in the blue box and then connect them with the yellow boxes which describe how these formats are mostly used.

It is used…

This format…

GIF

For example:

This data format is based on PostScript code. It can be imported into other programs. The embedded information can’t be changed. Graphics in this format can be pixel as well as vector orientated.

Every computer can read this format. It uses indexed colours (up to 256), therefore the file size of pictures is strongly reduced. It’s used for logos, graphics and images. The content of this format can be transparent, animated or interlaced.

This format is used for pixel graphics only. It can be handled on almost every platform. The information of a picture is stored in “tags”. This format needs a large storage space. Therefore, the format offers a lossless compression (LZW).

Based on PostScript, this format contains images, graphics, fonts and other information. The file size is very small and the quality of the data can be adjusted at the output. Additionally, the user can display the file and make changes in the document.

This is not only a format but also a way to compress. The advantage of this format is the small size of the file because data can be compressed high. There are several compression steps – the higher the compression rate, the greater the loss of quality

JPEG Joint Photographic Experts Group

PDFPortable Document Format

TIFFTagged Image File Format

GIFGraphics Interchange Format

 

EPSEncapsulated PostScript

It’s used for vector information as well as for image data that is not supposed to be manipulated by the user. You can store isolated figures, characteristic print lines and fonts with this format.

This format is, because of its small size, mainly used in the Internet or in quantity-optimized pre-press workflows (newspapers). The distiller of Acrobat uses this format for compressing pictures in a PDF-File.

The function of this format is to display images on the Internet. The size is small and there are three variants to display them. HTML uses this format to display pictures and graphics..

It is used in several digital workflows and it’s established as a standard for information interchange of complex data. It hasn’t existed as long as the other formats.

Colour and gray level-pictures in every size and resolution can be saved in this format. It is the most commonly used data format to place pictures into dtp-programs.

 

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