The basics of image format


In the past, when printed matter was printed by analog means, from the bottom plate, the film, to the printing plate, the eyes could take care of each process step by step. Finally, the plate was transferred to a printing press and transferred to paper. Improper photocopying or shortcomings on the plate can be indicated at the bottom stage or verified on the film, and can be found with the eyes.

However, today's progress in digital workflow is undoubtedly using data that cannot be seen with eyes. Therefore, it is necessary to make data and accept the aspects of it, so that a consensus data format can be achieved.

The definition of the format

Want to define the image format. It becomes a recording form when several image data are included in a file. The term “file” in the context of an image refers to a group of data when processing an image created by application software or processing with an image included in a scanner or the like. A file that is formed only by text data is called a text file.

The format of data records when creating a file is called the file format. It includes the image size required for image reproduction, resolution, symbolization methods, and the like and the image data itself. Even if the same image data, if the file format is different, the computer can not read the data, then there is a need for a common data called the intermediate format that can exchange data.

In general, when saving image data in application software, you can specify the file format. Therefore, in accepting data, it is only necessary to save it in a corresponding format.

In the era of CEPS, prepress engineering manufacturers each used a unique format. For example, Dainippon Screen has OMEGA format, Scitex has HandShake, Linotype-Hell and Crossfield, Scitex have jointly developed IFEN and so on.

In the current field of plate printing, the commonly used formats are EPS, TIFF, and PICT. Among them, EPS is the most commonly used format. The most striking thing of late is PDF. PDF workflows, machines suitable for output, and service firms have been introduced.

Various image formats

Here is a representative format for plate printing. Each of them has its own advantages and disadvantages. It can't be said whether it is superior or not. Some are under consideration by the ISO.


The abbreviation of Tagged Image File Format. The intention is to mark the image file format as a representative format supported by many application software. The attributes of the data itself, color, size, etc. are made up of files described in the data description section called the mark. According to this identification, determine various attributes or data forms. With the help of tags, the randomness of files is improved, and the exchange of data is also convenient between different application softwares and between different computers.


The abbreviation of TIFF for Image Technology.

It is a standard for expressing image data for printing using a TIFF structure. The TIFF file format is mainly determined for color separation images such as CMYK and is not dependent on the OS, but is applicable to the exchange format of raster data files used in the printing plate making. Continuous tone color (CS), line version (LW), high resolution continuous tone (HC), monochrome layer (MP), point combination BP, run-length 2 value (BL) And other various image data. Its expansion plan is also being discussed in ISO.


For each image data format of TIFF/IT, a format called profile 1 is specified. For each image data type of CT, LW, HC, MP, BP, BL, a standard for marking the information group and its value can be used.


The acronym for Encapsulated Postscript Format. Developed by Adobe Systems Inc., USA, it is a format that accepts Postscript data between software. Most situations are expressed in EPS. In order to confirm the arrangement and content of the data, a special picture format including a display screen is used in addition to the dedicated title text.

Because EPS is for Postscript, it is the de facto standard format when processing image data on various DTP software. A DCS (Desktop Color Separator) form has been used for printing. Due to adoption of DCS, color images are stored in 4 files of CMYK colors. As other specialties, you can use only images to cut them, and you can also use JPEG compression. When images such as text and photos are output by an output device such as an image-setter, the relationship is generally Postscript, and data can be stored in EPS.


Department of Picture abbreviation. Image format determined by Apple Computer of the United States. Almost all applications that work on macOS have helped. Also known as the Macintosh-specific format.


It is a shortening of the Joint Photographic Image Experts Group.

The standard of the color still picture scale coding method determined by ISO and ITU (The Electric Communication Association) is the most commonly used compression format in the field of plate printing. The compression rate is from 1/5 to 1/30. Due to the non-reversible compression relationship, some information is lost when the compression is reduced. When high compression rates and high quality reproduction are required, specific compression techniques are required.


The abbreviation of Portable Document Format means a portable file format. The file format advocated by Adobe Systems Inc. based on Postscript technology. Zooming can be done, and the outline of the text and graphics is perfect and the effect is excellent. It can also be handled without relying on a computer's working platform. Because it can be filled with fonts, it is called the standard format of this century.

Usually used for office business. For printing, there is a specialized PDF called PDF/X which is being studied by ISO.