Foreword

This standard is equivalent to the use of the international standard ISO 12647-2:1996 "Printing Technology - Mesh adjustment of color separations, proofs and printing process control of finished products - Part 2: Offset."
In adopting this international standard in an equivalent way, the structure and content of the original international standard are basically retained, and only the editors have made amendments to the rules for the compilation of the Chinese standard.
This standard consists of five parts: the scope of application, citation standards, definitions, technical requirements, print upper-level adjustments, and tone-adjustment methods. Among them: the method for measuring the increase value of the upper level and the adjusted value of the printed matter and the definition of several parameters are described in GB/T 17934.1-1999, "Printing technology, mesh processing, color separation, proofs and printing process control of finished products. Part 1: Parameters and Test Methods."
Appendix A, Appendix B, and Appendix C of this standard are the suggested annexes.
This standard was proposed by the People's Republic of China Press and Publication Administration.
This standard is under the jurisdiction of the National Printing Standardization Technical Committee.
This standard was drafted by: Beijing Institute of Graphic Communication.
The main drafters of this standard: Chen Shiwen and Chen Yaxiong.

ISO Preface

ISO (International Organization for Standardization) is a worldwide standardization agency composed of various national standards bodies (ISO member countries). The work of setting international standards is usually done by ISO technical committees. Each member group has the right to participate in the committee's work if it is interested in a standard project already established by a technical committee. International organizations (official or non-governmental) that maintain contact with ISO may also participate in the work. In the area of ​​electrotechnical standardization, ISO maintains close cooperation with the International Electrotechnical Commission (IEC).

The draft international standards proposed by the technical committee were submitted to the member bodies for voting. International standards must be approved by at least 75% of the member groups participating in the vote before they can be formally adopted.

The ISO 12647-2 international standard was completed by the ISO/TC 130 Printing Technical Committee.
The general title of ISO 12647 International Standard is "Printing Technology - Process Control of Mesh, Separation, and Printed Finishes" and consists of the following parts:
- Part 1: Parameters and measurement methods - Part 2: Offsets Appendix A to Appendix C of this standard is an appendix to the guidance.

introduction

In the production of halftone color reproductions, it is very important that the color separation personnel, proofing personnel and the printing staff predefine a minimum set of parameters that specifically determine proofing and printing of visual effects and other technical performance. This requirement makes it possible to properly implement the correct production of a qualified color separation sheet (without repeated testing) and the effective implementation of post-processes such as non-printer proofing and printer proofing for the purpose of simulating the visual effects of the final printed product as closely as possible.

In order for the proofs to be visually consistent with the particular print, non-printer proofs may require different solid color and tone increment parameters than their simulated print methods. This is due to the fact that substrates, colorants, and implementation techniques used in non-printer proofing may differ significantly from offset printing processes, causing differences in glossiness, light scattering (substrates or color formers), and transparency. In this case, it is best for the user or the printer to determine the appropriate amount of correction in advance.

It is necessary to distinguish between direct and indirect parameters. Direct parameters (as listed in this standard) refer to parameters that directly affect the visual effects of the image. The indirect parameter is a parameter that indirectly affects the visual effect of the image by changing the value of the direct parameter. Indirect parameters include:

- The thickness of the dichroic plate - the forward and reverse direction of the image - negative or positive - unevenness of the emulsion surface - whether or not there is a color mark or a nested mark

GB/T 17934.1 lists and explains the minimum set of direct process parameters required to specify the visual effects of proofs or printed products produced from a set of mesh-tone separations.

This standard lists the values ​​of the direct parameters specified in GB/T 17934.1, as well as the technical requirements related to the use of dichroic sheets for the production of halftone offset prints. Where necessary, direct and indirect parameters are also recommended.

Printing technology mesh control of process control for colour separations, proofs and printed products

Part 2: Offset Printing

1 Scope

This standard specifies the process parameters and their quantities used in the preparation of four-color offset printing or four-color print production in one of the following ways. These printing methods refer to thermosetting web printing, single sheets or Continuous form printing or proofing for these processes, and offset proofing for gravure printing. The selection of these parameters and their magnitude covers the entire offset printing process such as "color separation", "printing plate production", "proofing", "printing" and "surface finishing".

This standard applies to - proofing and printing processes based on color separation films;
- Proofing and printing without film copying, and gravure printing similar to film production systems;
——The proofing process is similar to four-color printing with four or more printing methods;
- similar to the line network and non-periodic screening method.

2 Reference standards

The words and phrases contained in the following standards are incorporated into this standard and constitute the provisions of this standard. When this standard is published, the versions shown are valid. All standards will be revised and all parties using this standard should explore the possibility of using the latest version of the following standards.
GB/T 8941.3-1988 Determination of specular gloss of paper and board with a 75° angle GB/T 11501-1989 Spectral conditions for density measurement of a photograph GB/T 17934.1-1999 Printing technology with mesh separation of colour proofs and printed products Production process control Part 1: Parameters and test methods CY/T 31-1999 Printing techniques Four-color printing inks Color and transparency Part 1: Sheet-fed and thermosetting web offsets

3 Definitions

This standard uses the definition given in GB/T 17934.1 and the following.

3.1 Offset plate (printing) plate
The surface is subjected to a coating treatment to produce a flat plate workpiece on which the ink transfer area and the non-transfer ink area are in the same plane.

3.2 positive-acting (offset printing) plaet
Offset plate for positive color separations.
3.3 negative offset printing plate negative-acting (offset printing) plaet
Offset plate for negative color separations.

3.4 Four-color continuous form printing four color continuous forms printing
Use a narrow format web for offset printing.

3.5 Commercial / Special Printing commercial/speciality printing
Plain sheetfed and non-magazine thermoset web offset.

3.6 Non-periodic (non-periodic) half-tone screens
Mesh network with no regular network and no fixed network lines.