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Tim Mouw

Metrology

Five Tips to Avoid Color Drift

It might be time to establish digital standards, document processes, and service measurement devices

Published: Tuesday, December 7, 2021 - 13:02

Color accounts for 60 percent of acceptance or rejection in consumer products. Maintaining accurate and consistent color is critical. If a color starts to drift, this leads to rework, wasted materials, and added costs.

To avoid color drift over time, consider the following.

1. Are you using digital color standards?

To produce accurate color, everyone across the manufacturing process and supply chain must use the same color standard. Based on spectral data, digital color standards remove subjectivity from color communication and ensure that everyone, from design to production, has real-time access to approved standards. This helps eliminate errors that occur when physical standards become old, faded, dirty, or damaged. Digital standards integrate with formulation and quality control software to help manufacturers quickly verify color accuracy throughout the production process. They also make it easier to identify and eliminate drift before it becomes a problem.


X-Rite NetProfiler

2. Is your spectrophotometer in good working order?

When it comes to measuring and verifying color, it’s important to ensure that all color measurement instruments are certified and have been maintained for optimal performance and consistency. Just like your car, spectrophotometers can drift over time due to age, wear, and environmental conditions. They need to be maintained and certified to ensure accurate readings. If your instrument is old and no longer supported, it cannot be certified by the manufacturer. As a result, you will not know if the device is measuring accurately until products are rejected during quality control or by the customer. For confidence in your measurement readings, upgrade discontinued devices to a new, certified instrument.

Today’s current and supported color measurement instruments are easier than ever to maintain. In addition to yearly recertifications by field technicians who clean, repair, and verify device performance, a company can use a tool like NetProfiler to adjust and validate instrument performance on a monthly basis. NetProfiler combines a set of standards tiles with cloud-based software to profile a device. As instruments drift over time due to extended use or changing environmental conditions, NetProfiler will make automatic adjustments to ensure you are always getting accurate measurements. It can also be used to reduce variation between devices and will inform you when the instrument needs service before it results in off-color products.

3. Do you track production variables?

There are many process variables that can impact color: Supplier, raw materials, operator, line, temperature, humidity, and many more. These different variables can quickly add up and put you out of color tolerance. For example, temperature can affect measurement readings through a phenomenon known as thermochromaticity. A change in season or a cold material sample might cause you to suddenly start jumping over tolerance.

Manufacturers should identify and assess which process variables have the biggest impact on color consistency and track this information across production for each sample measured.

4. Are you following documented measurement procedures?

Documenting and establishing standard operating procedures for manufacturing and quality control is essential. If you have multiple lines, shifts, and manufacturing locations, everyone must follow the same procedures for consistent, uniform output. Otherwise, you run the risk that items will not match. The same holds true for color measurement processes. If the first shift is measuring samples under LED light, and the second shift is using natural light, the measurements will vary and can lead to drift.

When creating and documenting procedures, consider the following attributes:

• Instrument geometry, such as sphere, multiangle, or 45:0
• Illuminant and observer
• Aperture size
• Color space (LAB, LCH)
• Tolerance
• Modes (for a sphere, SCI or SCE? For a 45:0, which M mode are you using?)
• Location of measurement and orientation
• Number of averaged measurements
• Sample presentation
• Backing material
• The environment, including temperature and humidity
• Age of the sample

5. Are you leveraging data and analytics to identify drift in production?

Once companies have identified the variable data they want to track, quality control professionals can leverage those data to better understand where color drift occurs in the process. Color quality-control software that syncs with measurement devices makes it easy to graphically see the color variation of a series of measurement samples. This software can plot whether failing colors are too light, too dark, too red, etc. Equally important, the software can be used to sort, group, and analyze process variables, making it easier to identify patterns and the cause of color variation in production.

For example, if you produce a set of samples using the same material and run it under a variety of different settings, the data may show a temperature increased or decreased, and dwell time is causing the color to shift.

Conclusion

If your color has started to drift, it might be time to establish digital standards, document processes, and service measurement devices. Work with your specifiers, suppliers, and third-party partners to confirm that everyone is using the same color standards and procedures. By monitoring and analyzing color data and variables throughout production, you can achieve accurate color from beginning to end and batch to batch.

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About The Author

Tim Mouw’s picture

Tim Mouw

Tim Mouw is the manager of applications engineering and technical support for X-Rite Pantone in the Americas. Mouw oversees a team of 20 technical support specialists that help customers manage and improve color quality control processes. Mouw has taught more than 300 color science courses throughout North and South America, Europe, Asia, and Australia. X-Rite helps customers communicate and manage color standards for raw materials, paper-based products, ink, photography, video, metal, glass, textiles, plastics and wood.