PDF/A in a Nutshell
The book about the new standard PDF/A by PDF/A Competence Center
Especially newspaper producer are familiar with the occasional display that is causing nothing but headache. All parts of the workflow get a hiccup when processing a problematic file. The file is either not processed at all or its output apparently is not correct. No time is left to get in touch with the supplier of the ad – and by definition, newspapers cannot wait.
Also in cases where designers used one or even many spot colors although the job is actually for a CMYK press run, color conversion to CMYK can cause problems, especially when transparency was flattened before converting the spot colors to CMYK.
As a last resort, the PDF can be converted to an image PDF (make sure to use CMYK as otherwise your separations will be spoiled). While Adobe Photoshop is a decent tool to achieve this, pdfToolbox makes it a matter of a click.
To open the Switchboard, click on the menu item "Switchboard" under the "View" menu or use the keyboard short cut "Ctrl-2" or "Cmd-2". Then click on the "Document" group icon.
Click on the "Image export" icon to go to the image export action.
1. Select the output format for the image export. Besides exporting to invidual TIFF, JPEG or PNG files, pdfToolbox 4.5 now also supports export to image PDFs, where each page is an image of the appearance of the original page.
2. The recommended color space for producing a print production ready PDF is CMYK. This ensures that the separations in the original PDF are maintained, and that for example black text still is rendered on the black plate only.
3. For most purposes, an image resolution of 300 ppi is a good compromise between amount of detail and file size. The images in the exported PDF will be compressed using lossless ZIP to avoid JPEG artifacts, and to keep vector objects crisp.
4. Always leave "Simulate overprinting" checked as otherwise the exported PDF may not look exactly the same as it would when output on print from the source PDF.
5. Click on execute to initiate the image export.
After completing the export, please double check the size of the exported PDF – as it has been saved to disk as a new file, please open it from there to display it.
1. On the left side, pdfToolbox "Visualizer" shows the CMY separations, not showing the black plate. Obviously none of the black text or vector objects show up in this view – which is a good sign!
2. On the right side, "Visualizer" shows the black plate only – all the black text is clearly showing up here.
When exporting a PDF to an image PDF, pdfToolbox ensures that the CMYK separations are maintained, and guarantees crisp text and vector objects in the print output.
Depending on the resolution chosen during image PDF export, text will remain sufficiently clear to be readable well enough. Look at the smallest text on the page using the "Loupe" in pdfToolbox to decide whether the resolution chosen is sufficient for your print production. As a rule of thumb: for newspapers 200 ppi is sufficient if no small text is present, otherwise 300 ppi should be chosen. For sheet fed offset 300 ppi resp. 450 ppi should be chosen.