PDFX

PDF/X is a family of ISO standard subsets of the Portable Document Format (PDF) designed for the exchange of graphics-rich documents in the printing industry. It specifies a constrained feature set and metadata to ensure a file prints consistently across devices and software, enabling reliable color reproduction, trapping, and page geometry in prepress workflows. PDF/X files are intended to be print-ready and self-contained, minimizing variability in production environments.

Conformance requirements typically include embedding all fonts (preferably as subsets), no password protection or external dependencies, and a declared output intent with an embedded ICC color profile for color-managed workflows. The file must use clearly defined color spaces and provide page boxes (such as media, crop, and bleed) along with marks and bleed information when appropriate. Encryption is not allowed and optional content is restricted in some levels.

Conformance levels include PDF/X-1a, PDF/X-3, and PDF/X-4, representing a progression of restrictions and capabilities. PDF/X-1a is the most restrictive: it requires all content to be embedded, prohibits transparency, and limits colors to CMYK and spot colors. PDF/X-3 adds support for ICC-based color management, allowing RGB colors that are converted during printing. PDF/X-4 further enables live transparency and optional content (layers) while preserving print reliability through defined output intents and color management.

Industries that commonly use PDF/X include offset printing, packaging, advertising, and high-end graphics. Manufacturers and service bureaus typically run preflight checks to verify conformance before printing, and most professional PDF workflows, RIPs, and proofing tools support PDF/X workflows.

History and status: PDF/X originated in the 1990s as part of the broader PDF standardization effort and is governed by ISO 15930. The standard has evolved through multiple parts and revisions to accommodate modern color management and desktop printing requirements.