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ISO 12647 — an introduction

June 30, 2009

In July, ippStar will organise a Monsoon Summit consisting of three workshops around the country to provide printers with a comprehensive understanding of the ISO 12647 standard. The one-day intensive and interactive workshops will include presentations by international experts involved in its development, implementation and certification-process. Over the next few months, IPP will publish a series of articles covering the various implications of applying the ISO 12647 standard to prepress and printing operations, writes Ron Augustin.

Quality check under standard viewing conditions

With the development of digital workflows and increasingly streamlined printing processes, standards have become paramount in every segment of our industry. File format, document description and exchange standards, from TIFF/IT and PostScript to XML, JDF and PDF/X, have transformed the industry tremendously over the past three decades. Colour reproduction and print quality standards, however, have been far more difficult to define and achieve. Driven mainly by advertising requirements, the newspaper industry has been the first segment to develop its own sets of standard print profiles, such as ICONS in India, SNAP and SWOP in the US, QUIZ and others in Europe, and ACER in Latin America.

After a lot of pressure from within the industry, ISO, the International Standards Organisation, revived earlier attempts toward a comprehensive quality standard by its Graphic Technology technical committee (TC 130), and published the first edition of the ISO 12647 standard in 1996. Two major amendments to the standard have been published in 2004 and 2007, and specific issues within the standard are under continuous improvement.

ISO 12647 has become the standard on which most printing specifications are based. It has targets for ink colour, trapping, grey balance and dot gain values, defined in 7 parts: Part 1: Parameters and measurement methods; Part 2: Offset lithographic processes; Part 3: Coldset offset lithography and letterpress on newsprint; Part 4: Publication gravure process; Part 5: Screen printing; Part 6: Flexographic printing; Part 7: Digital proofing.

Other ISO standards concerning the printing industry include ISO 3664 defining standard lighting and viewing conditions, ISO 2846 for process inks, ISO 12218 for platemaking, ISO 12643 for safety requirements, ISO 12646 for colour proofing displays, ISO 13655-56 for colour and density measurements, and numerous standards for digital data exchange.

ISO 12647-2 being the comprehensive and worldwide accepted quality standard for 4-colour offset printing, it basically consists of a list of reference parameters providing definitions for the transfer of files from prepress to press, quality requirements for predictable and reproducible print quality, and specifications for printing conditions determined by paper type, solid tone colour coordinates, dot gain characteristics for each colour, and tolerances in colouration, dot gain and trapping. The standard itself comprises not more than 18 pages, but refers to 4 other ISO standards (ISO 5 density measurement, ISO 8254 measurement of gloss, ISO 12642 characterisation input data, and ISO 12647-1 parameters and measurement methods) and is complemented in prepress by proofing standard ISO 12647-7. The standards can be ordered from ISO (iso.org), and cost between Euro 60 and 90 each. ISO 12647-2 compliant technical guidelines such as the Media Standard Print and visual test files such as the Altona Test Suite can be downloaded for free at bvdm-online.de and eci.org, respectively, where many supporting specs and generic colour profiles can be found as well. Similarly, ISO 12647-3 through 12647-6 define specifications for coldset, publication gravure, screen, and flexo printing.

Do we have a choice?
Process control procedures, quality control reporting, and ISO 12647 compliance are becoming standard practice in the relationship between international print buyers and their local supply chains, including the advertising agencies, prepress studios, packaging converters, and publication and commercial printing houses. The ISO 12647 standard has more relevance for printers than quality management frameworks such as ISO 9001, because it has a direct impact on the quality of their product and service offering. Its application is first of all in their own interest, because it provides them with a tool that enables consistent, measurable and repeatable print quality. Approximation of customer requirements is reached not by interpretation but by a defined set of target values and relatively narrow tolerances. Proofs and prints can be adjusted by means of colour profiles, faulty data can be detected easily, and print specs can be quantified, measured, documented and traced at any time in the process. Repeat orders and print jobs at different locations can be tuned to unambiguous specifications. Advantages include unified and optimised basic settings in prepress, press and postpress; realistic planning of production flows; alignment of workflows by clearly defined parameters; consistent results; minimising of mistakes and misunderstandings by clearly defined interfaces and responsibilities; less bottlenecks, interruptions and corrections; and consequently, cost savings. Clearly, customers benefit by predictable product quality, consistency within and between jobs, uniformity of repeat orders, and by being freed from many of the controls and controversies all of us have known too well in this industry.

Implementation
Different implementation guidelines for ISO 12647 describe the testing and control methods by which prepress and printing processes can be controlled, monitored and documented. Measuring devices with spectral and densitometric settings are used in combination with suitable testing elements such as control strips and test sheets. ISO 12647 specifications are used to set nominal values and tolerances for materials and equipment, in order to ensure that intermediary and final results provide predictable colour quality. Areas most affected by the application of these values in prepress are colour settings in Photoshop, the use of ICC colour profiles, compliance with PDF/X-3 standards, maintenance of basic parameters and data consistency (such as resolution and file formats), standardised proofing, and standardised platemaking. In printing, the implementation has most impact on the alignment conditions of the presses, the use of measuring devices and the adherance to control procedures, after initial test runs within predetermined tolerances.