ISO 28178:2022 — Graphic Technology — Exchange Format for Colour and Process Control Data

1. Introduction to ISO 28178:2022

ISO 28178:2022 defines an exchange format for colour and process control data in electronic form using either XML or ASCII formatted data files. This standard supports the graphic arts industry by providing a standardized method for sharing spectral measurement data, colorimetric data, and densitometric data between different software systems, instruments, and organizations throughout the printing and packaging supply chain. The format maintains both human readability when viewed in standard text editors and automated machine processing capability for integration into production workflows. Developed by ISO/TC 130 Graphic technology, this second edition updates the 2009 version with additional guidance on delimiters and sample identification to improve data exchange reliability for multi-colour printing workflows.

The standard addresses a critical industry need: consistent colour communication across the entire supply chain from design concept through prepress, proofing, production printing, and quality control. Without standardized data exchange, colour mismatches between different spectrophotometers, software applications, and production sites can lead to costly reprints, customer dissatisfaction, and production delays. The format supports all common graphic arts workflows including commercial printing, packaging, and publication printing, and is designed to accommodate both current and future measurement technologies. The standard also provides mechanisms for ensuring backward compatibility with data files created under the 2009 edition, protecting previous investments in measurement data archives.

2. File Format Specifications and Structure

The standard defines two parallel file formats that can be used independently, each with specific advantages for different technical environments:

Both formats use predefined tags and keywords with associated values organized in a structured preamble followed by data sections. The preamble includes essential metadata describing the measurement context and conditions:

Required preamble elements include document identification, creation date, creator information, and data source specifications, providing a minimum set of metadata for traceability and context. All optional elements serve to complete the measurement description for more demanding colour management workflows where precise knowledge of measurement conditions is essential for accurate colour reproduction across different instruments and sites. User-defined extensions are explicitly permitted for proprietary or application-specific data fields, ensuring the format can accommodate specialized workflow requirements while maintaining baseline interoperability between different organizations in the supply chain.

3. Practical Applications and Implementation Considerations

The standard supports four essential categories of colour measurement data for modern printing workflows: spectral reflectance or transmittance values across the visible wavelength range (typically 380-780 nm), colorimetric data expressed in CIE L*a*b*, CIE XYZ, or other standard colour space coordinates, densitometric values for traditional process control using CMYK density measurements, and process control data including press settings, substrate specifications, and quality metrics. Data tables within the file format can contain multiple columns with individually defined data formats, enabling efficient representation of large measurement datasets from automated spectrophotometric scanning systems. The format’s support for multi-column data tables is particularly valuable for quality control applications where each measured patch generates multiple simultaneous readings across different colorimetric metrics.

Engineering Design Insights

For software developers and system integrators implementing colour management workflows, the dual-format approach provides essential flexibility for different deployment scenarios. The ASCII format is particularly valuable for legacy system integration, quick debugging during development, and human-readable audit trails, while XML offers more robust structure for complex data relationships involving multiple measurements, conditions, and metadata. The 2022 revision specifically addressed the important issue of delimiter handling between decimal point and comma conventions in different regions, which is critical for international data exchange between printing facilities operating in different countries. Companies can add proprietary data fields through user-defined extensions while maintaining full standard compliance for interoperability with trading partners. When implementing file parsers, careful attention should be paid to encoding declarations, required versus optional elements, and appropriate error handling for incomplete or extended files. For production environments handling large volumes of colour measurements, automated validation against the format specification is recommended to detect structural issues before they affect downstream colour management processes. Many commercial colour management software packages now support direct import and export of the ISO 28178 format, reducing the need for custom format conversion tools in production workflows.

4. FAQs