Overview
ISO 28178:2022 - "Graphic technology - Exchange format for colour and process control data using XML or ASCII text" - defines a standardized electronic exchange format for colour and process-control data and the associated metadata. The format supports both XML (XML 1.0) and an extended ASCII keyword–value representation, preserving both human readability and machine readability. It is focused primarily on spectral measurement data, colorimetric data, and densitometric data, and is intended to be used alongside other graphic-arts standards that define the specific data content.
Key topics and technical requirements
- Dual formats: Supports an XML format (schema file iso28178_data.xsd) and an ASCII keyword-value format so legacy systems and modern workflows interoperate.
- Preamble + data sections: Files are split into a preamble (iso28178.preamble tag in XML) containing metadata, and a data section describing table definitions and table data.
- Predefined tags and keywords: The standard supplies a set of predefined XML tags and ASCII keywords to identify common information used in graphic-arts measurement exchange.
- Extensibility: Allows user-defined tags/keywords and XML namespaces so implementers can extend the format without breaking automated readers.
- Data tables and identifiers: Structured support for multiple data tables per file. Table descriptors include NUMBER_OF_FIELDS, NUMBER_OF_SETS, BEGIN_DATA_FORMAT / END_DATA_FORMAT, and BEGIN_DATA / END_DATA delimiters.
- Formatting rules: ASCII files use whitespace (space, tab, carriage return, newline) as separators; character string values must be enclosed in quotes; decimal separation uses the full point (.) and comments start with “#”.
- Machine and human readability: Designed so standard editors can view files and automated programs can reliably parse them.
- Normative XML schema: The XML schema (iso28178_data.xsd) is part of the normative specification and available from ISO.
Practical applications and users
ISO 28178 is practical for:
- Print production and prepress workflows exchanging measurement and control data
- Colour laboratories and QC departments capturing spectral, colorimetric and densitometric results
- Instrument manufacturers that output measurement files (spectrophotometers, densitometers)
- Software developers building RIPs, colour-management tools, MIS and process-control systems
- Service providers integrating legacy ASCII exports with XML-based systems
Adopting ISO 28178 streamlines data exchange, reduces interpretation errors, and supports automation in colour-critical processes.
Related standards
- Intended to be used in conjunction with other graphic-arts and colour measurement standards that define the specific measurement parameters, tag semantics and required data fields. The ISO XML schema and annexes in ISO 28178 provide examples and guidance for implementation.