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Understanding IEC 13660-02: Measurement of Image Quality Attributes for Hardcopy Output
A Technical Overview of the ISO/IEC 13660 Standard for Binary Monochrome Text and Graphics
Scope of IEC 13660-02
IEC 13660-02, formally adopted as CAN/CSA-ISO/IEC 13660-02, is the Canadian national adoption of the international standard ISO/IEC 13660:2001 — Information technology — Office equipment — Measurement of image quality attributes for hardcopy output — Binary monochrome text and graphic images. This standard establishes objective, repeatable methods for measuring key image quality attributes of hardcopy output produced by digital printers, copiers, and multifunction devices. It focuses exclusively on binary (two-tone) monochrome text and line graphics, excluding continuous-tone or color images.
The primary goal of IEC 13660-02 is to provide a common, vendor-neutral language for specifying and verifying image quality in office equipment. It defines a set of measurable attributes, such as character fill, line width, and void area, and specifies the test target design, measurement apparatus, and data analysis procedures. The standard is widely referenced by manufacturers, test laboratories, and procurement organizations to ensure consistent quality evaluation across different devices and technologies (laser, inkjet, dot matrix, etc.).
Technical Requirements and Measurement Methodology
Test Target and Setup
IEC 13660-02 prescribes a specific test target (often called the IEC 13660 test page) that includes a standard set of characters, line patterns, and solid areas printed at nominal sizes and resolutions. The target must be printed under controlled environmental conditions (temperature, humidity) and using default driver settings for the device under test. The standard defines the required illumination for measurement, typically diffuse lighting at 45°/0° geometry, and the minimum resolution of the measurement device (usually 1000 dpi or higher for scanning microdensitometry).
Image Quality Attributes
The standard defines 11 primary image quality attributes for binary monochrome output. These are measured from the printed test target using automated image analysis software. The table below summarizes the key attributes, their definitions, and the typical measurement method.
| Attribute | Definition | Measurement Method |
|---|---|---|
| Fill | Percentage of a specified area that is covered by ink/toner inside a character or solid patch. | Count of black pixels vs. total pixels in a defined region of interest. |
| Line Width | Average width of a printed line, measured perpendicular to its direction. | Edge detection and distance measurement across multiple segments. |
| Void Area | Area of missing ink/toner within a character or line, expressed as a percentage or total area. | Segmentation and pixel counting of holes in the printed area. |
| Blurriness | Edge sharpness loss; the transition width from black to white at the edge of a feature. | Measurement of the 10%–90% reflectance distance on a scanned edge profile. |
| Raggedness | Irregularity of a printed edge; deviation from a straight line over a given length. | Analysis of edge point deviations from best-fit line; reported as standard deviation. |
| Character Fill (Black) | Average density/log reflectance inside a solid character (e.g., “8” or “O”). | Reflectance measurement over defined interior area. |
| Background | Reflectance of the unprinted media (paper) in areas adjacent to printed features. | Reflectance measurement on a designated white patch. |
| Character Contrast | Difference in reflectance between printed character and local background. | Calculated from character reflectance and background reflectance measurements. |
Data Analysis and Reporting
The standard requires that measurements be taken from multiple instances of each test element (e.g., 10 different “e” characters on the page) and that statistical values (mean, standard deviation) be reported. For each attribute, the standard defines the region of interest (ROI), the algorithm for edge detection (typically a threshold based on the midpoint reflectance), and the method for aggregating results. All measurements are performed on the digital scan of the printed test target, following a calibration procedure using a certified reflection standard.
Implementation Highlights
Adopting IEC 13660-02 in a quality assurance workflow requires careful attention to hardware, software, and procedural factors:
Tip: When implementing IEC 13660-02 measurements, use a calibrated flatbed scanner with at least 1000 dpi optical resolution. Ensure the scanner is color-managed to linear grayscale and that the test target is placed using registration marks to minimize skew.
- Test Target Generation: Use the exact file provided by ISO (available from national standards bodies) or generate it according to the specifications in Annex A. The target includes a reference gray scale and geometric alignment marks.
- Environmental Control: Maintain temperature (23 ± 2 °C) and relative humidity (50 ± 5%) during printing and measurement to reduce variability.
- Image Analysis Software: Many commercial and open-source tools implement the algorithms specified in the standard (e.g., ImageJ with plugins, or proprietary packages). Validation of software against reference images is critical.
- Scanner Calibration: Use a certified reflection gray scale (e.g., Kodak Q-14) to linearize the scanner response to optical density. Perform calibration before each measurement session.
Warning: The standard does not apply to color or continuous-tone images. For those, refer to ISO 19751 (Image Quality for Colour Printers) or ISO 15790 (Photography – Reflection densitometry). Using IEC 13660-02 on halftone output can lead to misinterpretation of measured attributes.
Compliance and Certification Notes
IEC 13660-02 is widely used in procurement contracts and manufacturer specifications to guarantee a minimum level of image quality. Compliance typically means that a device can produce output that meets certain threshold values for the attributes listed above. For example, a typical procurement specification might require character fill ≥ 95%, line width variation ≤ 5%, and maximum void area < 0.5%.
Compliance Tip: To claim compliance with IEC 13660-02, organizations should conduct measurements in an accredited test laboratory or follow the standard’s procedures strictly and maintain traceable calibration records. The standard itself does not mandate pass/fail values; those are defined by the user or by other referencing standards (e.g., ISO 24790 for office equipment).
Many national adoption bodies (like CSA in Canada) have added a national foreword but kept the technical content identical to ISO/IEC 13660:2001. Therefore, IEC 13660-02 is technically equivalent to the international version and is accepted in global trade. However, some procurement bodies may require newer editions; note that ISO/IEC 13660 was confirmed in 2016 and is currently under review. Always check the latest version (ISO/IEC 13660:2001/Amd 1:2013 or any subsequent revision) for any amendments.
Important: Misuse of the standard can lead to erroneous conclusions. For example, if the target is printed at a resolution lower than specified, or if the measurement tool is not properly calibrated, the resulting attribute values may be misleading. Always follow the exact test target layout and measurement conditions defined in the normative sections.
Frequently Asked Questions
Q: Can IEC 13660-02 be used to measure image quality of color prints?
A: No, the standard is specifically designed for binary monochrome (black-and-white) text and line art. For color prints, refer to ISO 19751 or other standards addressing color image quality attributes.
A: No, the standard is specifically designed for binary monochrome (black-and-white) text and line art. For color prints, refer to ISO 19751 or other standards addressing color image quality attributes.
Q: What is the difference between ISO/IEC 13660 and IEC 13660-02?
A: ISO/IEC 13660 is the international standard published by ISO and IEC. IEC 13660-02 (more precisely CAN/CSA-ISO/IEC 13660-02) is the Canadian adoption that is technically identical. The same standard is also adopted in other countries (e.g., AS/NZS in Australia).
A: ISO/IEC 13660 is the international standard published by ISO and IEC. IEC 13660-02 (more precisely CAN/CSA-ISO/IEC 13660-02) is the Canadian adoption that is technically identical. The same standard is also adopted in other countries (e.g., AS/NZS in Australia).
Q: Is the test target freely available?
A: The exact digital file for the test target is part of the standard and must be obtained from a national standards body. Some organizations provide sample files for preliminary evaluation, but only the official files should be used for compliance testing.
A: The exact digital file for the test target is part of the standard and must be obtained from a national standards body. Some organizations provide sample files for preliminary evaluation, but only the official files should be used for compliance testing.
Q: How often should scanner calibration be performed?
A: The standard recommends calibration before each measurement session or whenever the scanner temperature changes by more than 1 °C. Use a certified reflection standard that is traceable to a national metrology institute.
A: The standard recommends calibration before each measurement session or whenever the scanner temperature changes by more than 1 °C. Use a certified reflection standard that is traceable to a national metrology institute.
Updated: 2026 — This article reflects the technical content of IEC 13660-02 (CAN/CSA-ISO/IEC 13660-02) and related best practices. Always consult the official standard document for authoritative requirements.