Cp.6 Traditional Image Assemble and Platemaking

1. Cp.6 Traditional Image Assemble and Platemaking Xi’an university of technology Prof. Dr. Cao Congjun

2. Terms • Stripping 手工拼版（make-up拼版) • Proof 打样 • Imposition 组版/拼版 Work and Turn Imposition 侧翻版 Work and Tumble Imposition 滚翻版 • Registration 套准 • Platemaking 制版 • Offset,Lithography 胶印

3. Section 1:Traditional Image Assemble • The combination of text and images to form a page occurs during the page “make-up”. In the production of conventional printing plates the complete page is put together manually by repro experts from text and images that exist mainly as cut films. The films are placed on a carrier sheet, adjusted for position, and fastened in place. The quality of the print depends directly on the precision and care of the makeup. • Film stripping is carried out on a light table (see also fig.). Its work surface consists of a glass plate that is illuminated from below with diffuse white light.

4. Fig. Prepress with conventional film stripping and digital master preparation(text, images, graphics) with EDP systems

5. Stripping Transparent Materials The Purpose of Stripping: Mechanical stripping is the process of assembling all pieces of film containing images that will be carried on the same printing plate and securing them on a masking sheet that will hold them in their appropriate printing positions during the platemaking process. The assembled masking sheet with pieces of film attached is called flat. The flat is generally tested on some inexpensive photosensitive material to check image positions and to ensure that no undesired light reaches the plate.This process is called proof.

6. Imposition • Imposition refers to placing images in the correct positions on the printing plate so they print in the desired locations on the final printed sheet. • The design of the printed piece • The type and size of the press • The type of paper

7. Fig.Layout sheet for page assembly with regard to the print sheet and arrangement of control elements and print finishing information; example: front side of a 16-page brochure, produced through three folds

8. Type of Imposition • One-side imposition • Sheet-wise Imposition • Ganged Imposition P110.Fig • Signature Imposition P110.Fig • Work and Turn Imposition P111.Fig • Work and Tumble Imposition P111.Fig

9. Elementary Stripping Techniques • Masking Sheets P113.Fig6.6 • The cylinder line • The gripper margin • The point where the image begins on the printed piece(Figure 6.6a) • The plate center line

10. Multiflat Registration • The Purpose of Registration Systems • Fig 6.19 Using complementary flats for double exposure • Fig 6.20 Using folding masks to control multiple plate exposure • Punch and Register Pin Method(6.22 & 6.23) • Multiflat Stripping for Process Color Work • Blueline Flat Method • Single Master Flat Method

11. Fig. Plate punch (CONTROL2000 register system, Bacher)

12. Proofing Transparent Materials The Purpose of Proofing Color proofs are necessary for judging the quality of multicolor products. For the printing side the color proof may be used to control the correct position of the individual color separations on the page, accurately registered assembly,the approximate overall color effect of the page or the representative color reproduction of the printed product to be produced.

13. Photomechanical Proofs Analog proofing Analog proofing, that is processes that are based on film, use colored diazo layers on thin films, which are individually exposed with the color separation halftone film of each respective component color, developed using the wet process, and transferred to a carrier material.

14. Fig. Analog proof: color sheets that have been produced from the corresponding color separation films are fastened on a white background in accurate register (Color Art System/Single Sheet type, Fuji)

15. Fig. Analog proof using a toner-based process. a Layer structure of the sheets with an adhesive layer (photopolymer) that loses its adhesive property during exposure with a positive film(the protective layer is removed prior to laminating onto the substrate/paper, for exposure the film is placed on the carrier base, then the carrier base is removed to apply the toner); b Toner adheres to the unexposed areas; c Devices for the analog Cromalin color proof (Cromalin, DuPont)

16. Press Proof Fig. Flat-bed offset proofing press (Korrex 2000, FAG). a Proofing press; b Plate fixture on the table; c Printed sheet on the flat-bed table

17. Digital Proof-soft proof a Monitor on the control console; b Image details of the print job on the monitor; c Checking the dot structure on the monitor Fig. Soft proof on the control console of a computer to press/direct imaging printing system(QM-DI, Heidelberg).

18. Digital Proof-Imposition Proof (Layout Proof) Fig. Imposition color proof with large-format ink jet printer (Sherpa,AGFA)

19. Section 2: Offset Platemaking Equipment for Proofing and Plating Exposure system Process System Light source calibration Lithographic Printing Plates Base Plate Materials Coating materials Surface Plate

20. 蛋白版和平凹版 锌或铝 PS 版 铝 多层金属版 图文部分用铜，非图文用镍或铬 Base Plate Materials • 版材的选择：既有较好亲油性又有较好亲水性 常用金属的亲油性顺序 Cu > Fe > Zn > Al > Ni > Cr Mechanical Graining,Chemical Graining p133 Nowadays, practically all printing plates are grained in an electrolytic电解process (anodizing阳极电镀),that is, electrochemical graining with subsequent oxidation.

21. Lightsensitive,diazo (photopolymer) pre-coated aluminum printing plates are now the predominant plates in printshops. The image transfer is produced via the different properties on the surface of such plates after they have been exposed and developed. The remains of the original light-sensitive coating or the light-sensitive coating changed by the effect of light are the ink-accepting(oleophilic) elements that create the image. The thin coating of aluminum oxide created by the special treatment of the aluminum base material forms a particularly stable water-attracting (hydrophilic) surface.

22. 重铬酸盐感光材料:Ammonium bichromate重铬酸氨 重铬酸盐：NH4Cr2O7 高分子物质：聚乙烯醇（PVA）、蛋白 干燥后具有感光性 • 重氮(Diazo)感光材料 重氮化合物或叠氮化合物： 天然树脂或合成树脂： 受光后发生光化学反应，发生分解或交联、聚合 Coating Materials • 平版制版用感光材料：

23. PS版表面显微照片

24. Fig. Aluminum printing plate with halftone dots. a Magnified a hundred times; b Magnified 2000 times

25. two types of photochemical reactions • There are two types of photochemical reactions when developing the printing plate: • hardening of the light-sensitive layer by light (negative platemaking), • decomposition of the light-sensitive layer by light(positive platemaking).

26. Platemaking Fig. Platemaking. a Positive platemaking; b Negative platemaking

27. If the light-sensitive coating is hardened photochemically, it becomes insoluble for the developer in the exposed areas. If, on the other hand, the light-sensitive coating is decomposed photochemically, the developer removes the exposed light-sensitive coating from the base (e.g., aluminum).These two different platemaking processes (positive and negative platemaking) require different exposures to create images,that is, different types of films that are produced in advance.

28. 感光原理及印版种类 重氮化合物见光分解，显影溶之露出铝基 空白 图文未见光，感光层不溶于稀碱 亲油印刷部分 阳像底片 1. 阳图型PS版：P（Positive）型版 亦称内型版：图文基础牢固，无需加亲油性金属增强。

29. 重氮化合物见光交联或聚合，使见光胶层不溶，具重氮化合物见光交联或聚合，使见光胶层不溶，具 有亲油性 印刷部分 未见光部溶于显影液，露出版基 亲水性空白 阴像底片 2. 阴图型PS版：N（Negative）型版 亦称外型版：需涂布补强基漆，以提高印刷部分耐磨性

30. Homework • P138 Review questions 2,9,13,14,16.