This topic is very old, but we still have to say a few words, because there are related topics - especially the operation of the film for packaging and printing has been switched from a film-based workflow to a computer directly to the imaging technology of the printing plate.
To be sure, some operational procedures have not changed: the design of the graphic file must match the diecut lines contained in the structured/CAD file; it can handle multi-spot color printing, trapping, dot compensation and proofing.
But the film is also the last killer in quality control tools. It provides a pleasant little time for the whole production process, which can make prepress service providers and packaging printers synchronize the workflow of both parties, and it may cause errors in printing and plate making processes, causing time and money to be wasted. The problem is eliminated.
In a fully digital CTP printing process, without the guidance of the prepress system, the color sequence of the ink at the time of printing cannot be used for proofing. For example, the inkjet proofing machine cannot cover the black text on an opaque golden background. If it is necessary to do so, it will inevitably delay the production of the product, but the printing machine can print smoothly. The figure above is a print sample from Esko-Graphics.
For example, who would care about the problem of printing color sequence before making plate? A designer who designed and packaged with Adobe's Illustrator did not worry about the black text being printed on non-transparent golden ink when working late at night. But because of such a small design flaw, it brought a lot of confusion to the printing shop, and it will defeat the bottom line of the packaging company's interest.
Push forward
Assuming that the problem occurred in the pressroom, then from here on to evaluate the workflow, and trace back to the designer, while solving the problem of how to remove the ink from the plate and paper, and then use the CTP process.
The increase in outlets is most affected by CTP. Digitally imaged plates can maintain both high-light and dark-tone dots at the same time. However, the dots of these two parts will be lost in the traditional film-making process, that is, only by adjusting the compensation curve and other elements in the process. Avoid this problem.
Jan De Roeck, director of global marketing for packaging software at Esko-Graphics, cautioned that many measurement tools do not measure 1% of change but only measure 5% or 10% of change. But if you want to keep 1% to 5% of the highlights and 92% to 99% of the shadows, you can only accurately measure the performance of each press, and carefully measure each press/ Ink/substrate combinations may produce results.
De Roeck insists that the measurement system must be able to distinguish between non-transparent and transparent inks. For color management and dot gain, it is to find out which one of them is the most important quality parameter.
To preserve the highlights and dark parts of the network must start with the source and color selection of the image. The same scanning tools/images are used for flexographic, offset, and gravure—it sounds good—especially the need for flexo printing has created the concept of digital masters, the independent use of output curves, and the inability of the dots to stand. Michael Rottenborn of Artwork Systems advocates the separation of scanning tools/images.
For the flexo CTP process, it is important to note that the details of the highlights must be manipulated in different ways. De Roeck cautions that the revision workers must remove the dirtiest dots before they output the plates, because these dots will destroy the entire printing effect.
Color management
ICC-based color management is slowly moving from commercial printing to packaging. But this seems to be a challenge for "cold bench software," because packaging printing almost exclusively uses spot color printing and special ink/color systems to match the tone of a customer's special brand.
Take Pepsi's bottle label, the technology to break down colors into spot colors is already mature. De Roeck said that packaging companies can both produce high-quality products and get huge profits. First, the type of ink that can be used for printing can be reduced, which can simplify the registration process; at the same time, it can also reduce the amount of consumables used in printing and reduce variable costs.
Similarly, the six-color and seven-color systems used by most packaging/printing companies can reduce intermediate cleaning and preparation times when printing different products. But FM6, Hexachrome, Opaltone, and other common systems are not good enough, and you must be absolutely safe when you print. While Scopes such as Artwork Systems' ArtPro and Esko-Graphics can support this type of workflow, general color management can only isolate 1.5% of the dots and other irregular but mathematically correct dots. Once these dots are printed There will be problems with the process.
Barcodes and CTP
Although the topic of RFID will replace bar codes in the future, bar codes are still crucial for every package. Typically, packaging and printing companies use the darkest ink in the field to print bar codes, but in the prepress process they have to be separated—possibly including other colors—so instead of decomposing color throughout the entire process. Into a variety of ink to change into the above-mentioned standard multi-color printing process.
Although bar code does not have a direct relationship with CTP, it is a good opportunity for packaging and printing prepress service providers who want to integrate themselves closely into the customer supply chain. Of course, there are many software tools that can be used to produce bar codes, but if your prepress system can be integrated into the customer's ERP system to automatically generate the correct bar code, you can reduce the cycle time and eliminate the chance of errors.
The example of bar code just wants to emphasize the necessity of process optimization. All the focus is on reducing the error rate in the prepress process so as to finally reduce the cost. Despite the “assembly line†category, products produced by successful workflows will continue to enter the customer's office, regardless of whether the price is reduced or the FDA's latest labelling notice.
Evidence is in the proofing process
The most intuitive change that may be related to CTP is the proofing process. Epson's various digital proofers have a wide color gamut and excellent sharpness. Although it goes beyond the need to calibrate the color and printer/ink/substrate combinations, you can still see how opaque text interacts with transparent inks.
Soft proofing is gradually being used in this process. For example, KPG's Matchprint Virtual, Artwork System's WebWay, and Esko-Graphics' WebCenter all provide browser-based readers. These systems allow the user to have the ability to inspect a TIFF file of 1 bit or more while seeing on the screen how the network cable was generated and how trapping is accomplished. In the future, hard copy proofers should be able to handle color fidelity problems for consumer packaged goods companies, and soft proofers will enable the prepress and print workers to ensure the correctness of outlets and spot color printing.
There are still some powerful 3D rendering tools. Esko-Graphics has a viewer-based VRML tool that can extend 2-dimensional images to 3-dimensional. The rendering function provided by the complete color solution allows the customer to rotate the package image in three directions, and finally see the finished product. Once again, this will also be part of the customer's supply chain.
Distortion is the cause of diarrhea in the packaging prepress process. With the increasing use of shrink wraps and unconventional sleeve labels, you must anticipate that these distorted images will change once they shrink/wrap outside the container. What looks like. Among the tools developed for this task is Artwork Systems' PowerWarp software.
Although a circular image or roller plate is made, this is only the first step in the market and requires a lot of investment. Among them is the problem of seamless splicing of the cable - matching the dots at the beginning/end of the image.
CTP on the final output problem - basically a 1bit TIFF picture - is very different from the traditional output. Their curves are different, though they still need to convert vector and bitmaps into binary files. But because CTP has to make the press do more work, this must be taken into account when screening. Due to the randomness of ordinary halftone dots in highlights, shadows, and midtones, the current perception of traditional screening is that it is out of date.
The flexographic CTP is still in its infancy. Although the technology has been confirmed, it is necessary to wait until the economic development reaches the point where most prepress service providers and packaging printers can bear this burden. CTP technology can produce better-quality packaging—you just need to build this workflow and take full advantage of the benefits of CTP technology.
Source of information: packagingdigest china