Export Settings for Print PDFs Using PDF/X-4 and Correct Compression

Most designers select PDF/X-4 in the export dialogue and assume the file is print ready. That assumption fails the job. The printer's RIP encounters RGB images, unembedded fonts, or live transparency that was never checked, and the job stalls. The PDF/X-4 specification is not a menu preset. It is a set of content-level rules enforced by preflight verification. A preset named PDF/X-4 does not check whether every placed image is CMYK, whether the total ink coverage exceeds 300%, or whether the font you used has an fsType bit that blocks embedding. Those checks require a separate preflight profile. Without it, the file is a gamble.

Adobe InDesign offers PDF/X-4:2010 as a built-in export preset. Selecting it sets the PDF version to 1.6, enables live transparency, and requires an output intent. It does not convert your RGB images to CMYK. It does not downsample a 72 ppi web image to 300 ppi effective resolution. It does not warn you that a font is licensed with an embedding restriction.

The Ghent Workgroup PDF creation specification, published in 2022, treats these gaps as the primary failure mode in prepress. The GWG 2022 specification requires that every image be in the correct colour space at export, that every font be subset and 100% embedded, and that the output intent match the press condition. InDesign's preset alone cannot guarantee any of that.

Compression in a print PDF is about balancing file size against RIP processing stability. The wrong choice produces a file the printer cannot open or one that prints with visible artefacts.

Image Compression

Use JPEG 2000 lossless for continuous-tone images and ZIP for images with large areas of flat colour. JPEG 2000 lossless compresses without discarding data. That avoids the blocky artefacts that appear when a RIP decompresses standard JPEG. Do not use automatic JPEG high. The Ghent Workgroup standard specifies lossless compression for all images destined for commercial offset.

Downsampling

Downsample colour and grayscale images to 300 ppi effective resolution. Downsample monochrome line art to 1200 ppi. Do not downsample above 300 ppi for colour images. An image at 600 ppi increases file weight without improving printed quality. The offset press screen ruling cannot resolve the extra detail. Use bicubic downsampling, not average or subsampling, to preserve edge sharpness.

Live Transparency and Blend Space

PDF/X-4 supports live transparency. Drop shadows, blend modes, and opacity do not need to be flattened at export. This is the single most important reason to use PDF/X-4 instead of PDF/X-1a. PDF/X-1a flattens all transparency into rasterised areas. That flattening produces opaque white boxes around drop shadows and coarse pixelation on gradients. A RIP that receives a PDF/X-1a file with live transparency will either reject it or apply its own unpredictable flattening. PDF/X-4 avoids that entirely. Set the transparency blend space to CMYK or Grayscale, not RGB, to prevent a colour shift at the RIP.

Printer marks and bleed dimensions are the mechanical reference the RIP uses to align and trim your job. The Ghent Workgroup standard, derived from ISO 12647-2, specifies a bleed of 3 mm (0.118 in) for commercial offset. US commercial print commonly uses 0.125 in (3.175 mm). Use 3 mm unless your printer specifies otherwise. The safe area, where no critical text or logo should be placed, is 3 to 5 mm inside the trim edge. Content outside that zone risks being trimmed off.

Printer Marks Settings

Enable trim marks, registration marks, colour bars, and page information in the export dialogue. Set trim marks to a line weight of 0.25 pt and a length of 5 to 7 mm. Set the offset distance for crop marks to 3 mm from the bleed edge. Registration marks should have a diameter of 5 mm. Colour bars should use the FOGRA Media Wedge V3.0 or IDEAlliance ISO 12647-7 Control Strip. These targets allow the press operator to measure ink density and dot gain during the run.

The Slug Area

The slug is an unprinted area outside the bleed where printer marks and job information sit. It is not trimmed off. Include the job name, date, and version in the slug area so that every sheet on the press floor can be identified. The slug is not part of the printed design. Do not place any visual element there.