Knowledge Base
Paper & Corrugated Packaging Color Measurement Glossary
Brightness (ISO) A measure of the reflectance of paper or board at 457 nm blue light, expressed as a percentage. Governed by ISO 2470-1. Higher brightness values indicate a whiter, cleaner-looking sheet. Standard instrument geometry: d/0°.
CIE (International Commission on Illumination) The international body that defines standardised color scales and measurement geometries used globally in color measurement. Source of the CIELAB and CIE L*C*h° color spaces.
CIELAB (L*a*b*) A three-axis color space in which L* = lightness (0 = black, 100 = white), a* = red/green axis, b* = yellow/blue axis. The most widely used scale for color tolerancing in paper and packaging.
Delta E (ΔE) The total numerical difference between two color measurements in CIELAB space. A ΔE of around 1.0 may be perceptible to the human eye under controlled conditions, though acceptable tolerances depend on the application. ΔE <2.0 is a common tolerance for acceptable color match in packaging.
d/0° geometry Diffuse illumination / 0° detection. Specified by ISO 2470 for brightness and opacity measurement of paper and board. Used in Technidyne ColorTouch X ISO and ColorTouch PC.
45°/0° geometry Directional illumination at 45° / detection at 0°. Approximates human visual perception of color. Specified by ISO 13655 for printed surface colorimetry. Also defined within TAPPI T 452 for reflectance measurement of paper and board using this geometry. Used in Technidyne ColorTouch X 45.
ISO 2470 Standard for measurement of diffuse blue reflectance factor (ISO brightness) of paper, board, and pulps.
ISO 2471 Standard for determination of opacity of paper. Expressed as the ratio of single-sheet reflectance to the reflectance of an infinite pad of the same paper.
ISO 11475 / ISO 11476 Standards for determination of CIE whiteness of paper and board under D65/10° and C/2° illuminant/observer conditions respectively.
ISO 13655 Spectral measurement and colorimetric computation standard for graphic arts and imaging. Defines how color measurements of printed surfaces are performed, including measurement conditions, geometry (e.g. 45°/0°), and data reporting.
Opacity The degree to which a sheet of paper prevents light from passing through it. Critical for print-through prevention in packaging. Measured per ISO 2471.
Spectrophotometer An instrument that measures the reflectance or transmittance of a material across the visible spectrum. In color measurement, the instrument analyses reflected light and outputs standardised color values (L*a*b*, brightness, whiteness).
TAPPI T 525 Test method for diffuse brightness of paper, paperboard, and pulp using a d/0° geometry. Widely used in North American paper mills.
Whiteness A multi-wavelength measure of how closely a paper or board surface approaches a theoretical perfect white. Measured per ISO 11475/11476 and incorporates contributions from optical brightening agents (OBAs).
Was this useful?
FAQs
-
Color inconsistency in corrugated packaging is typically caused by variation at one or more stages of the production process. The most common root causes are:
Base substrate variation. Changes in fibre furnish — particularly when recycled content varies — affect the brightness and color of the base sheet. Even small shifts in raw material can create visible color differences across board lots.
Coating weight and chemistry. Fluctuations in the coating weight of white-top liner, or changes in coating pigment batches, alter the reflectance characteristics of the surface before any printing takes place.
Ink formulation and press conditions. Ink density, ink lay-down, substrate absorbency, and press speed all influence how a color reproduces on corrugated board. Without color measurement at the press stage, drift can accumulate across a run.
Environmental conditions. Paper and board are hygroscopic — they absorb and release moisture. Changes in temperature and humidity affect reflectance properties. ISO 187 recommends conditioning samples to 23°C / 50% RH before measurement.
Instrument variation. Using different instruments, different calibration standards, or different measurement geometries between sites introduces measurement inconsistency that can be mistaken for process variation.
Controlling color across the corrugated supply chain requires measurement at each stage — from incoming liner, through the board plant, to the finished printed box — using calibrated, standards-compliant instruments such as the Technidyne ColorTouch X ISO and ColorTouch X 45.
-
ISO brightness and CIE whiteness are both optical measurements of paper and board, but they measure different properties and serve different purposes.
ISO brightness (measured per ISO 2470) is a single-wavelength measurement of the reflectance of a paper surface at 457 nm blue light, expressed as a percentage. It was originally developed to characterise the bleaching efficiency of pulp. A brightness of 90% ISO means the paper reflects 90% of the blue light directed at it. It does not account for the full visible spectrum.
CIE whiteness (measured per ISO 11475 or ISO 11476) is a multi-wavelength measurement that accounts for the entire visible spectrum and the contribution of optical brightening agents (OBAs). A paper that contains OBAs may have high CIE whiteness even if its ISO brightness is moderate — because OBAs re-emit UV energy as visible blue light, creating the perception of a brighter, whiter sheet.
In practical terms: ISO brightness is the standard measure for process control in pulp and paper mills. CIE whiteness is more relevant when specifying the visual appearance of paper for printing, where the full-spectrum appearance under different lighting conditions matters to the end user.
Both measurements are delivered by the Technidyne ColorTouch X ISO, allowing mills and converters to report against whichever standard their customer requires.
-
The correct geometry depends on what you are measuring and which standard applies.
For unprinted paper, liner, and board — measuring brightness, opacity, and whiteness — a d/0° (diffuse/0°) geometry is specified by ISO 2470 and TAPPI T 525. This geometry illuminates the sample from all angles and measures at 0°, averaging out surface texture effects and providing reproducible results on rough or uncoated surfaces. The Technidyne ColorTouch X ISO and ColorTouch PC use this geometry.
For printed or coated surfaces — measuring L*a*b* color values of inks, coatings, or decorated surfaces — a 45°/0° geometry is specified by ISO 13655. This geometry better represents how the human eye perceives color on a printed surface and is the standard for colorimetric measurement in graphic arts and packaging. It is also defined by TAPPI T 452, which governs reflectance measurement using this geometry for paper and paperboard applications. The Technidyne ColorTouch X 45 uses this geometry.
Using the wrong geometry for your application will produce measurements that cannot be meaningfully compared against the relevant standard or your customer’s specification. If your corrugated operation requires measurement of both unprinted board and printed output, a two-instrument approach ensures full standard compliance across all stages.
For guidance on instrument selection for your specific application, contact the Industrial Physics paper and pulp team.
-
The Technidyne ColorTouch X range is designed to go beyond measurement — delivering actionable data that supports process control decisions in paper and board manufacturing.
The instruments measure brightness, opacity, whiteness, and L*a*b* color values in compliance with ISO and TAPPI standards. But the process impact comes from how that data is used. As Industrial Physics describes it, the ColorTouch X is simple to use with a powerful process impact — combining ease of operation with measurement capability that directly informs production decisions.
Key process control capabilities include:
Trend monitoring. Tracking brightness or color values across a production run allows operators to identify drift before it leads to off-specification product. Early intervention — adjusting bleaching, coating, or furnish — reduces waste.
Batch-to-batch comparison. Comparing incoming raw material lots against a defined standard ensures that substrate variation is identified before it enters the process.
Calibration traceability. The ColorTouch X uses certified calibration standards. Industrial Physics provides calibration and verification standards for paper testing, supporting confidence in the traceability and consistency of measurement data.
Customer reporting. L*a*b*, brightness, and whiteness data can be output in formats that satisfy customer quality requirements, supporting supply chain transparency.
The ColorTouch X ISO, ColorTouch X 45, and ColorTouch PC are available from Industrial Physics, supported by a global service network offering installation, calibration, and ongoing maintenance.
Related Articles
-
Overview: How to Measure Color Consistency Color consistency is one of the most commercially sensitive quality parameters in paper and corrugated packaging production. Whether you are a paper mill supplying liner to a converter, a corrugated board manufacturer running print lines, or a brand owner specifying packaging, color that drifts between batches or production runs…
-
Color Consistency in Paper Packaging Color consistency is the ability to reproduce a defined, measurable color repeatedly and accurately across a production run, across substrates, or across multiple production sites. In paper and corrugated packaging, it is a critical quality parameter that directly affects brand integrity, print quality, and customer acceptance. For converters, brand owners,…
