On October 21st, 2011, “Joining Digital Technology and Leading the Printing Future – Hongsheng Digital Prepress Proof Technology Exchange Forum†jointly hosted by Bisheng Printing Network and Zhengzhou Hongsheng Digital Technology Co., Ltd. was held in Beijing Hunan Building. . This article is edited according to the speech of Mr. Shen Zhiwei, chief engineer of Beijing Shengli Printing and Printing Technology Co., Ltd. Dear experts, everyone in the afternoon, good afternoon, today, the organizer invited us to talk about it - digital process and color control, in fact, these two things are not the latest technology for our printing industry, it has been many years However, today I mainly share with you the experience of using our company. Some experiences in using PDF files The PDF file is a common format for the current digital process, which brings great convenience to the production of small files and previews. In production we found that each 16-page PDF file is approximately 500K to 4M. For example, in a separate experimental version, the PS file is 233M, and the PDF file is only 9.8M. The PDF file is faster in the digital process than the PS file. The PS file is interpreted as 4 minutes and 29 seconds, and the PDF file is only used for 2 minutes and 26 seconds. After the font of the PDF file is embedded, the digital process does not need to install the font. When using the PS file, the CID font must be purchased and loaded into the process. Digital workflow block diagram (graphic flow) Pre-fly File preflight refers to the file check process before the file is sent to the output device. The term pre-flight comes from pre-flight inspection before the aircraft takes off to ensure that the aircraft is fault free and crashed. The main pre-flight content is: PDF file version, information, format, secure page information, annotations, layout font type, name, inline, style, font with or without missing color processing, RGB graphics, spot color processing, color conversion image resolution, position, compression, image Whether there is missing text and line drafts to detect OPI Normalization Normalization is the creation of PDF files that conform to the printing specifications. The main contents are: PDF file version processing extremely thin line processing ICC file processing missing font processing low-precision image processing image transparency processing OPI image link Color matching RGB image to CMYK chart conversion between different standard CMYK images, spot color, printing, four-color processing Trap - trapping (trapping), overprinting (imprinting) 1. Solve some problems with poor application software 2. No trapping and imprinting in advance Purpose of color management The purpose of display, digital proofing, digital printing color management: Match the printed color The purpose of color distribution / scanner, digital camera color management: Match the color of the original or original As with general color management, color management for scanners and digital cameras requires three steps: 1. Equipment calibration; Digital camera color management evaluation: 1. Measure the Lab value of the digital camera color card 2. Measure the Lab value of the color conversion conversion graph 3. Calculate the color difference between the two. The purpose of display, digital proofing, digital printing color management: Match the printed color Printed colors? How to make printing stability become the key to color management For color management, standard proofs are printed under conditions of stable printing; Let the color management system produce a printed ICC file that correctly reflects the print status. How to make printing stable? 1. The temperature and humidity of the printing workshop are stable; Using international standards as our printing standard - ISO 12647-2 (offset) The main part of ISO 12647-2 (offset): (for paper type 1 and type 2) 1. Paper: L*=95 a* =0 b* =-2, where the tolerance L is ±3, and a and b are ±2. 2. Ink color: L*, a*, b* of Y, M, C, K, R, G, B are: The allowable error between the printed proof and the standard value is DE*ab ≤ 5 3, the tone value increases (the dot enlargement rate) According to the provisions of ISO 12647-2, the dot gain rate standards for Class 1 and Class 2 papers are: Among them: CMY adopts the A curve in the ISO 12647-2 standard, and K adopts the standard B curve. The tolerance at 50% is 4%, and the tolerance at 25% and 75% is 3%. The certification of color management for digital proofing (ie confirmation of the accuracy of digital proofing color management) is the main part of ISO 12647-7: 1, paper white: L * ≥ 95, a * =0 ± 2, b * =0 ± 2 Digital proofing color management certification process: 1. Use software: digital proofing certification software 2. Use hardware: spectrophotometer 3. Use test strip: (72 color patches) Digital proofing color management stability In actual production, the stability of digital proofing is more important than accuracy. Reasons for stability: 1. Change of ambient temperature and humidity 2. Change of print head with time of use 3. Change of printing ink with different batches 4. Change of printing paper purchased at different times Solution: Digital proofing software with digital proofing stability. A digital proofing software: uses printer calibration to ensure color stability. Print the image below (a total of 544 patches), then take the measurement. If the standard is not met, calculate and then print the measurement until the standard is met. Samples that have been calibrated for stability are subject to certification by digital proofing software. Article source address: http:// Other Baking Accessories,Silicone Oven Mitt,Adjustable Pizza Peel,Reusable Toast Bag,Silicone Leakage Shovel vchomy , https://www.jsvichen.com
2. The color characteristics describe the establishment of the ICC file;
3, color conversion.
2. The paper ink is relatively stable;
3, blanket, pad and its pressure stability;
4. The dampening solution is stable, including data of pH value, conductivity, temperature and alcohol content;
5, the surface state of the ink roller and water roller, the hardness and pressure meet the standard;
6, the printing machine speed is stable;
7, the most important thing is to master the ink and water balance, print the outlets; 
2, the color difference with the printing paper: DE * ab ≤ 3
3, the color difference of all color blocks (according to ISO 12642-2.): maximum DE * ab ≤ 6 average DE * ab ≤ 3
4, the color difference of the gray block: DH ≤ 1.5
5. Color blocks exceeding the color gamut: average DE*ab≤4
6. All color blocks of ISO12642-2 (a total of 1610 color blocks): average DE*ab≤4, 95% color block DE*ab≤6 