File production

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First, color and image (1) Convert image and color to CMYK
Most digital printing is currently limited to four-color printing, so all elements in the file must be converted to CMYK. Images stored in RGB format must be converted to CMYK. If you want to use gray component substitution color separation (GCR), in most cases, set the middle dark version, the maximum value of the black version is 95%, the total ink volume is 300%, and you can get better results. Spot colors (such as Pantone inks), two-color, three-color, and four-color must all be converted to CMYK.
(2) Save the image as TIFF or EPS
Image item storage force TIFF or EPS format. When scanning or storing continuous tone images, set the resolution to 200-300ppi, 133-15-Lpi. When scanning line drawings such as trademarks, set a higher resolution to avoid aliasing. Depending on the level of detail, the general setting is 600-800 ppi
In general, it is not necessary to first color-separate, store in desktop color separation (DCS), or store any conversion value. The image will be converted into CMYK by some software during the digital printing process, and the network overflow is calculated at the same time.
(3) Ensure OPI connection Some digital printing systems provide OPI replacement. High-precision images automatically replace low-precision images for layout. If you use low-precision image formatting, make sure the file name and connection are correct before sending.
Second, the file format The original software format to provide files Digital printing can only print PS files, but unless otherwise specified, you should provide the file's original software format. Such as Adobe PageMaker or QuarkXPress. Because digital printing requires special drivers or PPDs to generate Postscript files, some of the original file settings may need to be adjusted before turning to PS. If only PS files are provided, printing delays will result. Some printers can also accept other prepress format, such as Scitex Handshake
Third, trapping and superimposition (1) the use of the default trap width, but trapping is not necessary because the digital printing paper is not easy to shift and retractable, four-color register is basically not a problem, trapping can not be basic. Most digital printings do not provide the trapping function, but many files can use the trapping function of the application software. Generally, the width setting force is 0.25-0.5 points. For those more complex colors, it is necessary to consult with the printer for proper trapping.
(2) Black overprint The monochrome black version is suitable for the trapping width when printing overlaid, but if overprinting a large area of ​​color, multicolor overprinting is used to generate a rich black color. For example, 40% cyan, 30% magenta and 30% yellow plus 100% black are used. Rich black ensures the coverage of toner and ink, while preventing the appearance of the background.
4. Imposition Some digital printing systems include typesetting software. Imposition is based on the layout of your file, the type of digital printing, and the amount of printing for your platemaking. If your file needs to be folded, you need to make the page into a big version. Some digital printing systems include typesetting software. But for some digital printing systems that do not include imposition software, you first have to send the files to the plate making center or other printing house to make the imposition. In general, web printing is larger than the imposition of a sheet of paper.
V. File Transfer There are many different ways to send files to the printer, depending on the size of the file and the characteristics of the press. Smaller files can use floppy disks, larger files, SyQuest active hard drives, Lomega Zip compressed hard drives, Exabyte tapes, or CDs. You can also contact the printing house and ask them about the formats they use.
Some printers transmit electronic files via telephone networks, file transfer protocols, or global wide area networks. Unless you have a high speed connection, it is generally not recommended to use electronic transfer files.
VI. SPECIFICATIONS In order to ensure the correct printing of files, it is important to provide operators with file specifications, file lists, and samples including page breaks, images, colors, and handouts.
(1)Provide a copy of the proofs Usually you need to provide a laser print proof of the file and explain your requirements to the printing factory. Although the color and resolution of proofing are not the same as digital printing, the operator can use this to determine the location of colors, images, and pages.
(2) Provide as much as possible imposition styles and handoff examples If you provide a good version of the file, then you need to provide a large version of the style. Regardless of whether you make a make-up or not, you will need to provide the folds to the output center, which will display the arrangement and binding of the pages.
(3) Providing a font Create a font folder in the file disk and copy all the fonts used in the file. The full name of the body is listed in the specification sheet for easy searching.
(4) Provide a directory of files Provide a directory and all components of a printed file, including the file itself, high-precision image files, low-precision image files for typesetting, fonts, text, or images for variable data printing.
(5) Fill in the specifications. Provide complete specifications, such as those attached to the back cover of this book or provided by the printing house. The specification lists all the details of the wide file, such as image resolution, font requirements, paper requirements, trim size, and binding method. If you send files through the network, some printing companies also require you to provide an electronic specification.

Different requirements File production varies by job, especially variable data printing, imposition and OPI replacement. Apple or Windows operating systems also have an impact on file formats or storage media.
In addition, different digital printing owners, such as service companies, prepress companies, printing plants and newcomers, each have different printing experience and requirements. You can often contact the printing company to find out about their requirements for file production, and what color calibration, imposition, binding and archiving services are available. They will provide you with different software production files.