Print Standards, Specifications & Methods: A Practical Guide for Package Printing

ppzhan reports: In flexible packaging and package printing, standardization is often understood through three practical categories: standards, specifications, and methods.

A standard is broadly used and must pass evaluation and recognition by a governing body such as ISO. A specification gives detailed requirements for a particular job. A method describes the route, technique, or procedure for doing something.

In printing, ISO12467 is positioned as an industry standard. GRACoL and SWOP are specifications: they use characteristic data sets to define specific printing processes and materials. G7 is a method used to tune proofing and/or printing systems so they achieve the intended gray balance and tonal curve.

The core industry standard: ISO12467

ISO12467, Graphic technology — Process control for the production of half-tone colour separations, proof and production prints, was developed from combined data supplied by print quality committees in numerous countries. As a series of standards, it offers a compact parameter set covering technical attributes and visual characteristics for different printing processes. It gives manufacturers and print practitioners guidance for bringing equipment into a standard condition. Measurements taken at those printing plants can then support ICC color profile creation and proofs that match press colors.

ISO12647 supports information exchange among printing practitioners, prepress departments, and print buyers.

ISO12647 is built upon standards covering ink, paper, measurement, and visual viewing conditions.

ISO12647 contains seven parts. Each part addresses a different printing process and defines the small values of that process's parameters.

ISO12647-1: Process control for the production of half-tone colour separations, proofs and production prints: parameters and measurement conditions

ISO12647-2: Offset lithography

ISO12647-3: Coldset offset lithography on newsprint

ISO12647-4: Publication gravure printing

ISO12647-5: Screen printing

ISO12647-6: Flexography

ISO12647-7: Proofing processes working directly from digital data

Industry specifications PSO, GRACoL, SWOP and JapanColor: helping printers meet ISO standards

PSO (ProcessStandardOffset), the offset production standard, was created by Fogra, based in Munich, Germany, for BVDM (the German Printing and Media Industries Federation) so Germany's printing industry could implement it. PSO is also founded on ISO12647-2. It follows ISO12647-2 closely, adds supplementary rules, especially for digital proofing, and in cases where solid colors conflict, gives midtone color priority.

GRACoL, General Requirements for Applications in Commercial Offset Lithography, is a color reproduction specification for sheetfed offset lithography. GRACoL7 aligns with ISO12647-2 and uses the neutral print density curve, or NPDC, as a central element to define standard printing conditions and how they are achieved.

The gap between PSO and GRACoL is quite small. Both approaches argue that midtone control matters more than solid color control.

SWOP® is aimed at web offset printing and serves as its color reproduction specification. SWOP applies to rotary offset printing that uses ISO-specified inks and papers. There are two SWOP specifications: SWOP3 for printing on paper No. 3 and SWOP5 for printing on paper No. 5.

JapanColor is a specification and certification system from the Japan Printing Machinery Association. Its purpose is to encourage wide adoption of print standards across Japan's printing industry. JapanColor follows ISO standards and resembles GRACoL and PSO. It provides guidelines for sheetfed offset, newspaper, and web offset printing, and those guidelines have been specially adjusted for the Japanese printing market.

Industry method G7: the route to GRACoL and SWOP. G7 is a proof-to-print control method that offers a newer way to calibrate press and/or proofing color. From print buyer to design agency to printing plant and back to the print buyer, G7 creates a closed-loop, visually based control method. With it, printing can take place on virtually any press or substrate while keeping a common, consistent visual result. G7 is not limited to commercial printing; it also applies to publication and newsprint printing, flexographic printing, screen printing, and inkjet printing.

G7 rests on data imaging, spectrophotometric technology, and computer-to-plate technology. Its underlying idea is that visual appearance — how an image looks to the human eye from dark tones to light tones — is governed mainly by gray tones, not by measuring printed dot area. The name G7 comes from gray calibration technique (G) and the seven ISO inks (7). It stresses gray balance data in highlights and midtones rather than density targets such as solid density and dot gain for each color. G7 defines gray balance and the neutral print density curve (NPDC) and uses them as the basis for calibration and image reproduction. This helps ensure that files created with G7 produce similar visual results across any printing process.

Standardization means asking printers to follow simple rules accepted by industry experts and their customers. The ISO12647 unified standard is a simple procedural framework that makes printing more predictable and efficient. More importantly, printing supported by color measurement and color management technology can deliver image quality and consistency, raise the quality of products delivered to customers, and cut time and resources for printing plants and their clients.

——This article is reprinted from China Packaging Network (pack.cn), original link: http://news.pack.cn/show-362179.html