In the fast-paced world of print and packaging, achieving precise color accuracy is a critical challenge. Whether you're matching brand colors, controlling ink density, or ensuring quality consistency, selecting the right color measurement instrument can make all the difference.
Understanding Color Measurement Instruments
Selecting the right instrument for your print operation depends on factors such as production environment, measurement requirements, and industry standards. There are several types of instruments designed for different color assessment needs, including densitometers, spectrophotometers, and automated scanning solutions.
Densitometers for Ink Density Measurement
Densitometers have long been a staple in the print industry. They measure ink density, indicating how dark the ink appears, which correlates with ink film thickness. While effective for controlling ink on press, densitometers only measure the presence of Cyan, Magenta, Yellow, or Black and do not provide detailed color accuracy using L*a*b* values. This limitation means they cannot detect ink contamination, which can lead to inaccurate color reproduction.
Spectrophotometers: The Key to Precision Color Matching
Unlike densitometers, spectrophotometers offer a more advanced solution for color assessment. These instruments measure colorimetric data, allowing printers to compare the printed ink’s color to precise L*a*b* target values. By assessing color differences using ΔE measurements, spectrophotometers help maintain strict brand color tolerances.Modern print standards prioritize L*a*b* values over traditional density targets. The eXact 2, for instance, provides both density-based process control and L*a*b* measurements for color accuracy. Additionally, tools like X-Rite’s BestMatch guide operators in making density or ink strength adjustments to achieve the closest possible color match, ensuring optimal print quality.
Advanced Capabilities: eXact 2 Plus Spectrophotometer
For those requiring even greater precision, the eXact 2 Plus model includes additional capabilities such as:
- Evaluation of substrate whiteness and brightness
- Measurement of ink opacity and metamerism
- Display of spectral reflectance curves
These features make it an excellent tool for both pressroom and ink room applications, allowing for thorough color assessment across multiple stages of production.
Automated Color Bar Scanning: Enhancing Efficiency
When evaluating print quality, measuring a single ink patch is not enough—operators need insights into multiple ink zones. Automated color bar scanning solutions provide faster, more comprehensive color assessments.
eXact Auto-Scan & IntelliTrax2
- eXact Auto-Scan is a cost-effective solution designed for small to mid-size printers that measures full color bars using a laser sight for accurate alignment, making it ideal for sheets up to 40 inches wide.
- IntelliTrax2 is an integrated scanning solution for mid to large-size commercial and folding carton printers features a look-ahead camera that automatically locates the color bar, eliminating manual intervention and streamlining press control.
Both instruments integrate seamlessly with closed-loop press control systems, which automatically adjust ink keys based on real-time measurements. This significantly reduces makeready times and ensures tighter color control throughout production.
Prepress Calibration & Profiling
For prepress applications, devices like the i1 Pro 3 Family are designed for print and imaging professionals who need accurate color from printers, displays, and projectors. They also allow users to track and verify monitor and print quality while capturing spot color measurements. These instruments measure thousands of patches on specialized charts to adjust press curves and simulate production printing conditions. While highly precise, they are not built for the rugged demands of a pressroom.
The Science Behind Spectral Reflectance & Measurement Geometry
All these instruments discussed use 45:0 measurement geometry. This means:
- The light source is set at a 45-degree angle
- The reflected light is measured at 0 degrees
This setup replicates standardized viewing conditions and ensures accurate spectral reflectance data. By analyzing the reflected light at different wavelengths, these color measurement instruments create a unique color signature, which allows for precise color matching and quality assessment.
ISO Standards & M-Modes: Ensuring Consistency in Color Measurement
To maintain consistency across different measurement devices, the International Organization for Standardization (ISO) established standards like ISO 13655 and ISO 3664. These define the M-modes used in spectrophotometers:
- M0: A legacy condition without standardized UV light handling
- M1: Standardized UV light measurement, ensuring accurate color readings on substrates with optical brighteners
- M2: UV-cut mode, filtering out UV light for specific digital print applications
- M3: Used in offset litho printing to measure wet ink (commonly in Europe)
If your substrate contains optical brighteners, choosing the correct M-mode is crucial for maintaining accurate color reproduction. M1 aligns with modern ISO 3664 viewing booth standards, ensuring colors appear as expected under standardized lighting conditions.
Choosing the Right Spectrophotometer for Your Workflow
Selecting the right color measurement instrument depends on your specific needs. Densitometers provide basic ink density readings, while spectrophotometers offer the accuracy required for color-critical applications. Automated scanning solutions, such as eXact Auto-Scan and IntelliTrax2, further enhance efficiency and accuracy by integrating real-time press control.
By leveraging the power of these instruments and following ISO standards, printers can ensure accurate and consistent color reproduction, meeting the stringent demands of the print and packaging industry.
Investing in the right tools today will result in improved quality, reduced waste, and greater customer satisfaction in the long run.
Ready to take your color evaluation to the next level? To learn more about X-Rite color measurement instrumentation for print and packaging applications, get in touch with our Color Experts.
