PDF Print Preflight Checker

About the PDF Print Preflight Checker

Choose a PDF and get a print preflight in your browser. For every page you see the finished size with its trim and bleed boxes, the fonts (embedded or not, subset, type), the resolution of each image at the size it is printed, the colour spaces in use (RGB, CMYK, spot colours), transparency, and which pages are a different size or turned the other way. The problems are gathered in one list, and every page has its own details.

The checks follow the page boundaries of ISO 32000-1 and what print workflows ask of PDF/X-4 files (ISO 15930-7). The limits are yours to set: 300 ppi, 150 ppi and 3 mm of bleed are starting values, and your printer’s specification comes first. Print the report, or save it as text or CSV. The file is read on your device and never uploaded.

Common uses

• Checking a brochure, book or poster PDF before you send it to a printer.
• Finding images that look sharp on screen but will print soft because they are too small for the size they are placed at.
• Making sure fonts are embedded and that the trim and bleed boxes are set in a file that should be print-ready.
• Finding pages that are a different size from the rest, or turned the other way, before the pages are imposed on sheets.
• Seeing which spot colours and RGB elements a layout contains before the plates are made.
• Giving a client or a colleague a printable report of what a file contains.

How each check works

• Page boundaries. A page can define up to five boxes (ISO 32000-1 §14.11.2): the MediaBox (the sheet), CropBox, BleedBox, TrimBox (the finished page) and ArtBox. The CropBox defaults to the MediaBox, and the BleedBox, TrimBox and ArtBox default to the CropBox. The finished size is the TrimBox; without one, the CropBox or MediaBox is taken and the page is flagged.
• Bleed. The space from the TrimBox out to the BleedBox on each side, as the page is seen. When there is no BleedBox, the CropBox or the MediaBox is used, as the standard says.
• Fonts. Found by following the text that is really drawn (pages, drawings they use and form fields that print). A font is embedded when its font program is in the file; a name that starts with six capital letters and a plus sign is a subset. Fonts used only for invisible text, as in the text layer of a scan, are a note, not a problem.
• Image resolution. The pixel size of an image divided by the size it is drawn at, measured in both directions; the lower counts. An image that is drawn more than once gets its lowest value. Black-and-white images are judged at twice the limits. Images only one or two pixels wide or high, which are fills and gradient strips, are judged in the other direction only.
• Colour. The colour spaces that paint something: text, graphics, gradients and images. Spot colours are listed by name. The registration colour “All” is flagged because it prints on every plate.
• Transparency. Opacity below 100%, blend modes other than Normal, soft masks, and images with an alpha channel.
• Sizes. Pages are grouped by finished size, whichever way they are turned, and then by orientation.

Starting values

Commercial print: 300 ppi good, 150 ppi lowest, 3 mm bleed, RGB and a missing TrimBox are warnings. Office and digital: 200 and 100 ppi, no bleed check, RGB is fine. Large format: 100 and 50 ppi, for posters and banners seen from a distance. These are common rules of thumb, not standards, so follow the printer’s own numbers where they differ. Prepress sources usually describe a bleed of 3 to 5 mm.

What this is not

It does not certify PDF/X conformance. A PDF/X-4 file is expected to have all its fonts embedded, a stated output condition (an output intent), a TrimBox or ArtBox, and no encryption, and it may use transparency and layers. This tool reports the PDF/X version the file declares and whether an output intent is present, and checks the items above, but only a PDF/X validator checks everything else.

Sources

• ISO 32000-1:2008, Document management — Portable document format — Part 1: PDF 1.7, §14.11.2, Page boundaries.
• ISO 15930-7:2010, Graphic technology — Prepress digital data exchange using PDF — Part 7: Complete exchange of printing data (PDF/X-4).
• Prepressure, PDF/X-4 and Prepressure, the five page boxes: practical descriptions of what printers expect.

Limitations

• It is not a PDF/X validator and does not render the pages. Total ink coverage, overprint, trapping and whether the artwork really runs into the bleed are not checked.
• The resolution comes from the size the file places the image at. The picture data is not decoded, so an image that was enlarged from a smaller one (high ppi, little detail) and the quality of a JPEG cannot be told.
• Content on layers that are switched off is checked like the rest. The drawing instructions of Type 3 fonts (the bitmap fonts of some older typesetting programs) are not followed, and neither are the images that only serve as soft masks for fades and shadows.
• Annotations and form fields are checked only if they print; comments and fields without the Print flag are ignored.
• A page with more than 4 million drawing instructions is only read up to that point, and the result says so.
• A password-protected or restricted PDF has to be unlocked first with Unlock PDF.

Privacy

Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.