Printing Consultant And Service

preface

Color is the core of printing and reproduction work. Today, printing enterprises pay more and more attention to the improvement of printing color management methods when printing falls into the situation of meager profit and homogeneity. At present, the increasingly popular certification of printing enterprises is a useful exploration for enterprises to improve the quality of color reproduction. Among various certification systems, the G7 certification system of GRACoL is the most concerned one.

Up to now, hundreds of enterprises in mainland China have obtained G7 accreditation, and the application of printing standardization has begun to penetrate into small and medium-sized enterprises. These certified enterprises are mainly offset printing and prepress enterprises, and have also obtained the G7 Targeted or G7 ColorSpace level. The G7 recognized enterprise qualification lasts for one year, and the enterprises must be re certified every year. Therefore, G7 certification is not the end point. The ultimate goal of G7 certification is to carry out data, standardized and standardized production and maintain a long-term, stable and repeatable printing state.

　　

 

G7 Process and G7 Certification Introduction

GRACoL is an American offset commercial printing specification organization. It is a subcommittee responsible for offset printing technology research under IDEAlliance. G7 is a new method of printing standardization correction, detection and control created by the organization. So strictly speaking, G7 is a process control method. This method focuses on the control of neutral gray and emphasizes the effect of visual gray balance. Where, G represents the gray scale value calibration, and 7 represents the seven basic colors defined in the ISO12647-2 printing standard: cyan, magenta, yellow, black, red, green and blue. This method can be applied not only to the calibration of printing equipment, but also to other CMYK output devices, such as inkjet printers, laser printers, etc; In addition, when G7 method is used for general correction, there is no special requirement for paper, ink, number of screening lines, printing and output system, etc.

　　

 

G7 certification refers to the use of G7 calibration method to calibrate the printing system. When the performance and tolerance of the paper and ink used must meet the requirements of ISO12647-2, the entire printing process will finally meet the requirements of various standards of ISO 12647-2, so as to obtain the certificate of "G7 certification". The certified printing enterprise information will be included in G7 database for query, so as to provide printing enterprises with a wider range of customer trust and customer sources. G7 certification can be divided into different levels according to the existing resources and conditions of customers.

G7 certification level

1、 G7 Grayscale compliance requirements

G7 Grayscale is the lowest level in the G7 approved enterprise plan. Offset printing, digital printing, flexographic printing, and screen printing enterprises can all pass this level, provided that they meet the requirements of neutral gray. During certification testing, the neutral gray requirements of the left and right P2P will be measured. During certification testing, the left and right P2P will be measured to check whether neutral gray meets the requirements.

　　

 

2、 G7 Targeted compliance requirements (ISO or non ISO standard paper can be used)

Offset printing and digital printing enterprises can pass the G7 Targeted level. In addition to meeting the neutral gray requirements of G7 Grayscale, CMYK and RGB must also meet the requirements. CMYK ink up to ISO 12647 is required; For paper, ISO or non ISO standard paper can be selected. If the enterprise uses non ISO standard paper, it can recalculate the printing target value by using the concept of "substitute corrected aims". If the printing sheet meets the requirements, the enterprise can obtain the qualification of "G7 Targeted Relative". The enterprise can also choose to use ISO standard paper for certification. If the printing sheet meets the standard, the enterprise can obtain the qualification of "G7 Targeted".

　　

 

3、 G7 Colorspace compliance requirements (ISO standard paper must be used)

G7 Colorspace is the most difficult level in the G7 approved enterprise plan, suitable for enterprises engaged in offset printing, digital printing or prepress (such as plate making or providing digital proofing services). To get this grade, you must use ISO standard paper; At the same time, in addition to meeting the G7 Targeted requirements, the entire data of IT8.7/4 or TC1617 must also meet the requirements.

　　

 

G7 Certification Advantages

For printing enterprises

The G7 correction method can improve the tonal level of printed materials and the neutral gray performance of printed materials. Better neutral gray performance means more accurate color restoration, which fundamentally conforms to the printing essence of "color reproduction".

The implementation of G7 process brings about higher production efficiency and significant saving of production preparation time

The production of products is on the road of being replicable and repeatable

The best density control and neutral ash control methods used in G7 certification provide means and ideas for the production process control of printed materials, and the production of products is on a reproducible and repeatable road

Improve the communication between various departments within the enterprise, and increase the trust between different production links

Printing enterprises can achieve higher customer satisfaction by implementing standardized implementation processes

Improve the popularity of the enterprise and provide printing enterprises with a wider range of customer trust and customer sources

It enables them to have a better predictability of their products

Improve the communication between product design and printing, so that buyers can trust their suppliers more

It ensures that the product quality of different products of the purchaser, multiple printing of the same product and the use of products from different suppliers have a good consistency certification application

Printing enterprises can apply for G7 certification to G7 certification authorities in the region, or directly contact relevant G7 experts to apply. James Chen, a senior G7 expert of Kaiyin Technology

Before G7 certification, all enterprises must first apply to APTEC Hong Kong for P2P color table attached with QR Code, and relevant G7 experts need to provide customers with the test version of the printed sheet designated by APTEC. It is recommended that G7 approved enterprises should use full test sheets, namely, split sheets or 4-opening sheets, and the area covered must be at least 70% of the printing press.

Project preparation

Although G7 itself is not a true ISO standard, G7 certification requires that the materials, tools, measurement conditions and methods, and observation environment involved in the certification process must meet the requirements of relevant ISO standards. Therefore, before starting the certification process, the printing enterprise must make corresponding preliminary preparations.

Ink: G7 certification requires that the ink used must meet the corresponding ISO 2846 standard, which has made clear requirements for printing four-color ink (except G7 GrayScale grade, which is not required, it is recommended to use standard ink)

 

Paper: G7 Colorspace: The color difference between the paper and the LAB value of paper white required by GRACoL 1, SWOP 3 and SWOP 5 must be less than or equal to 3; G7 Targeted: The color difference between paper white and the LAB value of paper white required by GRACoL 1, SWOP 3 and SWOP 5 should be less than or equal to 5. If the color difference of LAB value is greater than 5, the applicant company shall apply in the way of [Paper white compensation adjustment].

 

Measuring tools: During the implementation of G7 certification, some professional measuring instruments and measuring software will be used to obtain the necessary testing data during the certification process. All color measurements must comply with ISO 13655 standard, spectrophotometer (X-Rite eXact, X-Rite I1IO, X-Rite I1Isis), and plate measuring instrument (such as X-Rtie ICPlate2 XT), and the calibration report has not expired.

 

Equipment calibration: Before the formal certification test, the printing enterprise must carry out necessary testing and calibration for CTP and printing equipment, and ensure that the equipment can be stably and correctly produced.

 

CTP calibration: Adjust the CTP focal length and exposure according to the guidance provided by the CTP manufacturer to ensure accurate reproduction of dot information; Detect the running state of the plate washing machine, control the pH value of the developer in an appropriate range, and ensure the stability and controllability of the physical and chemical state of the CTP plate making system.

　　

 

Calibration of printing machine: the printing machine (including consumables) shall be maintained in a stable state, and its related physical and chemical parameters shall be checked to see whether they meet the requirements. In order to better understand and control the status of the printing machine, necessary printing machine tests should be carried out. The items to be tested mainly include: dry density decompression test, mechanical ghost, starting bar, printing register and other tests. Adjust the printing machine according to the test results (if necessary, ask a printing technician to debug) until the printing machine is debugged to the best working condition.

Observation environment: G7 certification requires that the sample viewing conditions of the printing machine stand meet the ISO standard. The standard observation conditions of the printing industry are given in ISO 3664, which requires that the light source for printing meet the following requirements: the color temperature reaches 5000K, and the color rendering index (CRI) is not less than 90.

project implementation

After the printing enterprise confirms that it has completed the necessary preparations for certification, it can start the G7 certification process. A G7 certification expert must guide the audit on site during the whole certification process. G7 experts went deep into the printing enterprise to introduce G7 certification knowledge, interpret G7 correction methods, use certification tools and other training for relevant personnel of the enterprise, so that printing enterprise employees can understand the whole certification process, understand the key links of certification, and preliminarily master G7 correction methods.

　　

 

G7 certification knowledge training

G7 experts went deep into the printing enterprise to introduce G7 certification knowledge, interpret G7 correction methods, use certification tools and other training for relevant personnel of the enterprise, so that printing enterprise employees can understand the whole certification process, understand the key links of certification, and preliminarily master G7 correction methods.

The first round of linear printing

In the original state that CTP does not load any curve, output G7 certification specific test version linearly to record layout dot information, so as to better control the plate making process in the future;

When printing on the machine with this test plate, the printing state must be adjusted to meet the requirements. Use the spectrodensitometer to find the best field density of the printing machine. After the printing is stable, take several printing samples according to the sampling rules.

　　

 

CTP compensation correction

The necessary information is obtained by measuring and extracting specific elements on the printing sample, and the CMYK correction result is obtained by using Curve software to assign a new target value to RIP and complete the CTP correction.

　　

 

The second round of certification printing

The CTP system loads the correction curve made above, and prints with the best density for the first time. In order to ensure that the two printing states are as consistent as possible, the two printing cycles are completed by the same crew on the same day, and all settings of the printing machine remain unchanged. Samples shall be taken according to rules under stable printing conditions, and the samples shall be submitted to G7 certified experts on site.

　　

 

　　

 

G7 success guarantee - GMG Colorserver color conversion consistency

With GMG ColorServer, your data can be printed immediately and quickly reach the G7 goal. GMG's MX technology (integrated into GMG ColorServer) can produce the highest quality color space conversion. This technology retains the black channel, stabilizes the color, and achieves unmatched shadow clarity to provide consistent, obvious and outstanding effects, which is unmatched by any other solution on the market.

　　

 

GMG color conversion is a four-dimensional conversion from RGB CMYK or CMYK CMYK directly, maintaining the independence of the black channel

　　

 

(Use GMGCMYK conversion properties file for color conversion)

　　

 

(Use ordinary ICC conversion characteristic file for color conversion)

Audit and certification

G7 certification experts make on-site evaluation according to the printed samples. If the on-site evaluation is passed, G7 experts will submit the two samples to the certification authority for final evaluation, with a period of about 14 working days. If passed, the printing enterprise will receive the G7 certification certificate and logo issued by the G7 certification authority, and the enterprise information will also be included in the G7 certification database on the website for query.

　　

 

Maintenance of G7 certification system

This is the most important part. G7 certification is valid for one year. If you want to keep the certification, you must pass the annual audit once a year. Therefore, G7 certification is not the end point. The ultimate goal of G7 certification is to carry out data, standardized and standardized production and maintain a long-term, stable and repeatable printing state.