There are various file formats that service bureaus will be willing to accept for the purpose of generating output. Depending on the contents of a document, it is sometimes better to send work to a service bureau in vector format, while other times, a bitmap image will do. The following are the most commonly used file formats when generating a document that will be output professionally:
This is the native file format generated by CorelDRAW and is accepted by all Corel Approved Service Bureau (CASB) members. If can contain both vector and raster information as well as text. CASB members and other service bureaus who are equipped with CorelDRAW can accept files of this type and can apply the necessary prepress settings to the file. For individuals who are not familiar with the prepress process, this is usually a preferred file format because it relieves them of the need to properly prepare the document for output. CDR files can also contain embedded fonts and externally linked objects.
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Encapsulated PostScript is a file format which was created by Adobe for the purpose of output to PostScript devices. Files of this type can contain vector and raster information as well as text. An industry standard, EPS is perhaps the most commonly used file format when dealing with graphic design and professional output. Also, in the event that a service bureau is using software other than CorelDRAW, it is likely that they will be able to accept and output a document which has been saved in EPS format. When an EPS file is created in CorelDRAW, the option to create a header is provided. Usually, the header will range from 72dpi to 96dpi, however it can be set as high as 300dpi. When viewed on screen, the header is usually displayed and may result in the image appearing to be a low quality bitmap. This is to be excepted and if the EPS file is output to a PostScript printer, the bitmap header will be dropped and the vector file will be output.
The EPS Export dialog box in CorelDRAW permits the user to choose whether or not a header is generated (disabling this option will result in a gray box being displayed on screen when the EPS file is opened or imported. Again, this will not affect output when printed to a PostScript device) on export and, if so, whether the background of the header is to be transparent. Resolution of the header can also be adjusted from 12dpi to 300dpi with 72dpi being the default setting. Text can be exported as text or as curves and if exporting text as text, the option to include necessary fonts becomes available.
An ICC profile can be applied to the document when exported based on the current composite printer profile or the current separations printer profile. Alternatively, one is not required to apply an ICC profile and can disable this Color Management feature if desired. The color mode that bitmaps are exported as can also be specified as CMYK, RGB or Grayscale, OPI link can be maintained, fountain steps can be specified and can be set to automatically increase.
The Advanced tab of the EPS Export dialog box provides even more options (mostly pertaining to output) including PostScript Level, Bitmap Compression, Trapping and Bleed.
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Portable Document Format, like EPS was create by Adobe. PDF was initially created for the purpose of being able to easily distribute documents which could be viewed in a reader (also provided by Adobe) at no charge. Since its inception, PDF has gained popularity and is quickly becoming the common file format for use when preparing files to be sent to a service bureau or other individual.
CorelDRAW 12's ability to publish documents directly to PDF eliminates the need for other PDF generating software, saving designers time and money. The Save as PDF dialog box allows the PDF Style to be selected. Available styles include: PDF for Document Distribution, PDF for Editing, PDF for Prepress and PDF for Web. Also, Custom settings can be applied by clicking the Settings button to the right. When defining custom Publish to PDF settings, users have access to a full range of export options.
Under the General tab, the name of the PDF file is displayed along with other reference information such as the export range, compatibility level, author name, and PDF style. The Objects tab provides compression settings for use with bitmaps, text and line art, bitmap downsampling options and text and font settings. The Document tab offers the ability to configure bookmark settings while the Prepress tab allows for bleed to be included and for printer=s marks (crop marks, file information, registration marks and densitometer scales) to be added to the output file. The Advanced tab provides various settings allowing document overprints, halftone screen information, spot colors and OPI links to be preserved. In addition, fountain steps can be adjusted and EPS files can be output as a preview or as postscript. Color management can also be enabled under the Advanced tab and files can be embedded if desired. The Issues tab will report any preflight issues which can potentially alter or otherwise affect the PDF file when it is generated. If there is a desired to not have certain issues displayed, these can be enabled and disabled by clicking the Settings button.
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Practically any service bureau will accept a PRN file, however, if something needs to be edited, manipulated or adjusted, the service bureau will not be able to do this. PRN files are created by the printer driver and will provide what the printer would typically output, but in a single file. In CorelDRAW, a PRN file can be created by enabling the Print to File check box under the General tab of the Print dialog box. When this is enabled, clicking Print will prompt the user to specify the location where the file is to be saved. If creating a PRN file that is to be separated, plates can be saved as individual files, creating a PRN file for each one.
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Tagged Image File Format (TIF) is perhaps the most commonly used bitmap file format when sending information to a service bureau for output. With support for lossless compression, various color modes and transparency, it is a versatile standard which is viewable both on Windows and Macintosh based systems.
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Joint Photographic Experts Group (JPG) is another commonly used file format when there is a requirement to distribute information. This file format is often used for web rather than for professional output as it uses lossy compression.
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CompuServe Bitmap (GIF) is another file format most used with web graphics, however, depending on the image type and contents, can be used for professional output as it uses lossless compression. Its main downfall is that support is limited to 8-bit color or grayscale (256 shades) and that it is not ideally suited for use with files that contain thousands or millions of colors.
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