PDF/X (PDF Exchange) is a subset of Adobe PDF that eliminates many of the color, font, and trapping variables that lead to printing problems. You can verify that a PDF document is PDF/X-compliant in Adobe Acrobat 6.0 Professional before submitting the document to a service provider, and then embed the verification results in the file. You can even specify additional criteria for validating the PDF file, such as image resolution or the total number of plates allowed. And if you're using Distiller, you can verify the PDF/X compliance of your Adobe PDF files as you create them.
Verify PDF/X compliance in Distiller
You can verify that Adobe PDF files are PDF/X-compliant as you create them if you convert them from PostScript files in Distiller. In Distiller, choose PDFX1a or PDFX3 from the Default Settings pop-up menu if you want Distiller to use the standard defaults and to create a PDF file from the PostScript file only if it's PDF/X-compliant. Or, choose Settings > Edit Adobe PDF Settings, select the PDF/X tab, and choose a PDF/X specification. Then choose whether Distiller should continue or cancel the job if the resulting PDF file is not PDF/X-compliant.
Two types of PDF/X formats are typically used. PDF/X-1a supports only a CMYK (and spot color) workflow, targeted to a specific output device. Color management, transfer functions, and halftone screen frequencies are not allowed. PDF/X-3 supports a color-managed workflow in addition to CMYK and spot colors; transfer functions are not allowed; halftone screen frequencies are restricted.
Preflight the PDF/X file
To validate an existing Adobe PDF file, open it in Acrobat 6.0 Professional. Then choose Document > Preflight. In the Preflight Profiles dialog box, click PDF/X. Choose the PDF/X-1a or PDF/X-3 specification from the pop-up menu at the top of the Preflight PDF/X dialog box, and then click Verify.
Add restrictions, if necessary
In the Preflight Verify PDF/X dialog box, select Run Additional Checks if you want to add restrictions that are not part of the PDF/X standard. You can specify the total number of color plates, the minimum resolution for halftone or bitmap images, and for PDF/X-3, whether calibrated (device-independent) colors are allowed in addition to CMYK and spot colors. When you have made your selections, click Verify.
If more color plates are included than you allow, the document doesn't pass PDF/X verification. If the resolution values for halftone or bitmap images are lower than the values you specify, the images are flagged as errors.
View the preflight results
In the Preflight dialog box, click Report to see the verification results for your document. If you want to save the report as a separate file, click Report in the Preflight Results dialog box, and then specify a name, location, and file type for the report.
Preflight identifies aspects of your document that are not PDF/X-compliant, but it doesn't modify the file to make it compliant.
Validate the file to embed a report
In the Preflight Results dialog box, click Validate. When prompted, click OK, and then click OK again. Click Done to close the Preflight Results dialog box.
When you validate the file, Acrobat adds a validation stamp to the Adobe PDF document to inform prepress service providers and other users about the validity of the inspected document. The stamp embeds the preflight profile, which can be extracted later; embeds the results of the preflight report, which can be viewed using Preflight on another computer; and creates a time stamp. To view the time stamps and validation details for a file, click Validation in the Preflight Profiles dialog box, and then select a validation and click Details.
Verify multiple PDF/X files at once
If you routinely verify Adobe PDF/X files, consider running a batch-processing sequence that verifies the file and saves reports in locations you designate. For instructions, see "Inspecting multiple Adobe PDF files at once" in Complete Acrobat 6.0 Help.
This tip is reprinted with permission from Adobe.com.
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