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Many quality control (QC) professionals in manufacturing focus on variables like formulations, processing impacts, and contamination when considering which factors cause color alterations in their products. But for certain applications and in extreme environments, one unseen variable can cause equal damage to color consistency — temperature.

Even minor temperature variations can quickly ruin a batch or turn QC into expensive guesswork. The fluctuations can influence a sample's optical properties, alter light interactions, and impact measurement data reliability. As a result, maintaining color confidence in extreme conditions requires both strict protocols and powerful equipment to mitigate the environmental variables and uphold data integrity.

What Causes Temperature to Alter Color Measurement Results?

Understanding how temperature alters measurement results requires examining both the material-level changes and environmental factors that impact spectrophotometric analysis.

Thermochromism

Thermochromism is the phenomenon of a material exhibiting a reversible change of color in response to temperature changes. For example, think of novelty cups that turn from blue to green when filled with hot or cold liquid. This color change isn't the result of user error, but instead a temporary alteration in the material's optical properties that causes the material to reflect or transmit different proportions of light across the visible spectrum.

As the temperature of the contents starts to normalize to room temperature, the original color gradually returns. In such products, these color alterations are the goal for the desired effect. In others, thermochromism is a consequence to avoid, making consistency the key to preventing it. 

It's important not to confuse thermochromism with thermal degradation, an irreversible color change arising from extreme temperatures that can impact long-term color stability.

Environmental Instability and Material State Changes

Extreme temperatures can trigger physical changes in many samples that impact color perception, depending on the application. For example, thermal expansion and contraction can alter surface textures, changing how light reflects off the material and, in turn, the resulting measurements.

Measuring the color of hot liquids poses similar issues. As temperatures rise in these samples, bubbles and vapor often form that cause light to scatter differently, influencing appearance.

Additionally, temperature fluctuations can create secondary effects, such as the formation of condensation on sample surfaces. This excess humidity demands well-defined surface preparation protocols to ensure accurate readings.

Among the many challenges facing modern global manufacturers, regulatory compliance ranks at the top. The laws encompass product color standards to uphold consumer safety, advance best practices, and promote standardization. Operations that cross borders also span all these different legal frameworks that cover color and color measurement, from the FDA and USDA to ASTM, ISO, and JIS. Failing to adhere to all applicable standards has real, costly consequences, including material waste, penalties, and fines.

Spectrophotometry is the best solution for ensuring consistent, compliant color measurements. As the universal color translator, these devices provide objective, repeatable data that simultaneously satisfies multiple regulatory frameworks.

Variations in Regional Color Standards and Their Scope

The standards maze goes beyond bureaucratic differences to reflect real industrial priorities and their regulatory enforcement.

Organizations like ASTM and ISO primarily establish measurement methods that instruct manufacturers how to capture readings. For example, ASTM E1164 dictates the geometric conditions required for obtaining spectrophotometric data, such as d/8° or 45°/0°, while ISO 11664 — which is equivalent to CIE standards — defines the fundamental calculations for colorimetry.

In contrast, regulatory bodies like the FDA and USDA rely on these established methods to set the acceptance criteria. For instance, the USDA has specific Color Grades for products like tomato paste and orange juice. Calculating these specific grades requires extracting data using instruments equipped with the correct measurement geometries.

In Japan, Japanese Industrial Standards (JIS) for color measurement align closely with international CIE and ISO principles to ensure global consistency.

As a result, the true challenge for manufacturers isn't documentation and paperwork. It's having the right color measurement solution to bridge these different regulatory frameworks.

The High Costs of Inconsistent Measurement Protocols

Noncompliance with color standards isn't an option. Aside from potential regulatory fines and penalties, violations can lead to:

• Rejection of batches at incoming QC: Customers may turn away entire shipments, essentially doubling shipping costs with return logistics.
• Reworks due to failed color audits: Reformulating, reprocessing, and relabeling products reduces efficiency and profitability.
• Loss of contracts: Manufacturers may face reputational damage and lose future revenue opportunities for failing to deliver to specs and on time.
• Product recalls: If faulty goods hit the market, manufacturers must absorb the costs of recalling the products, which can range into the millions.
• Market exclusion: Repeated violations can result in being banned from selling in certain areas.

Plus, there is a substantial hidden cost to inconsistent measurement protocols — managing separate inventories for different regions. These separate streams mean more variability in raw material colors and less flexibility to redirect products based on demand shifts.

The Pitfalls of Visual Evaluations Across Multisite Operations

Manually evaluating color is an insufficient approach, and one that won't satisfy regulators. The process is unreliable since human color perception varies by individual and observation conditions. Differences in lighting, sample presentation, and operator fatigue will naturally arise, and all can significantly influence the accuracy of your color evaluations.

Visual assessments are also impossible to quantify precisely, so there's no way to document compliance objectively and share that evidence with regulators in other jurisdictions — you can't email a visual impression as proof.

What happens when the blue on Line A doesn't match the blue on Line B? Or when today's production run doesn't match yesterday's? In manufacturing, consistency equals quality. Nowhere is that more visibly evident than in your product color, where consumers will immediately notice any discrepancies. As you scale production across lines that span different facilities — and sometimes even continents — ensuring color harmony can become increasingly complex.

Understanding the importance of consistent color, knowing the challenges to achieving it, and learning how you can attain it can help you develop effective color-control strategies for your production processes.

Why Is Color Consistency Critical?

Inconsistent color has real-world impacts on your brand reputation and bottom line. When color is repeatable and consistent, you benefit from:

• A better brand perception: Customers have fewer reasons to question your quality or your product's desirability, flavor, freshness, and safety. 
• Fewer rejects and less rework: Goods that meet your customers' color specifications and expectations are less likely to result in costly rejects and rework, saving you time, money, and resources.
• Higher conformance with industry standards and regulations: Certain products and industries have strict color standards or regulations, such as pharmaceuticals and food dyes. Consistent color helps ensure your goods conform to the required frameworks and meet safety requirements.

What Are the Challenges of Achieving Consistent Color?

When production scales across multiple lines and facilities, several key challenges to color consistency arise:

• Raw material variations: The color and quality of raw materials often vary, especially when suppliers differ due to geographic location, availability, or supply chain diversity. Batch-to-batch inconsistencies also frequently occur in the plastics industry, where dynamic concentrations of recycled polyethylene terephthalate (rPET) in raw materials can dramatically impact final appearance.
• Influences in the production environment: Facilities may experience different environmental conditions, from humidity to heat and more, that can contribute to color alterations. Equipment may also vary widely and cause color inconsistencies.
• Variations in process parameters: If facilities differ in their production workflows, methods, or techniques, color consistency becomes more challenging. For example, variations in key process parameters like time and temperature will lead to differing color outcomes.
• Outdated color assessment approaches: Relying on antiquated measurement techniques like visual color comparison increases the potential for inconsistencies. This approach is too subjective, unreliable, and error-prone to uphold consistency effectively.

Plastic recycling is essential as the world continues to emphasize sustainability. Recycled plastic pellets from post-consumer and industrial waste offer value in various applications, including traffic cones, plastic chairs, detergent bottles, trash cans, and flower pots. 

Ensuring consistent color in products made from reprocessed materials can be complex. Here at HunterLab, we offer a range of solutions to measure the color of recycled pellets for precise results.

Challenges in Measuring Recycled Materials

Quantifying color in recycled plastic pellets presents unique challenges, such as:

• Material variations: Recycled pellets contain plastics from different sources, resulting in color variations. They are often blended to achieve a desired color. Color measurement can help ensure consistent blending ratios and a uniform final product color.
• Contamination: Foreign materials present in recycled pellets can affect color measurement accuracy. Implementing measures to minimize contamination in recycled pellets can improve color consistency.
• Physical form: Recycled pellets vary in size, shape, and opacity, affecting how light interacts with the material during measurement. These properties demand the right equipment and measurement methods for precision and consistency.

Best Practices for Precise Color Measurement

Spectrophotometers/colorimeters are the industry standard for precise color measurement. These devices analyze how light interacts with a sample and quantify the intensity of wavelengths across the visible spectrum to translate color into numbers. The following best practices will help you make the most of this technology to support your goals:

• Prepare and present samples accurately and consistently: It is crucial to maintain consistent sample preparation. Per ASTM D6290-19, operators must use a clean, optically clear and scratch-free sample cup filled to a sufficient depth to ensure effective opacity. Additionally, covering the sample cup with an opaque cover is crucial to block ambient room light and prevent external interference during measurement.
• Measure across a large area: The larger the sample area measured, the more precise and repeatable the results. Refer to ASTM D6290-19 Standard Test Method for Color Determination of Plastic Pellets for guidance on proper measurement methods. Specifically, the standard recommends taking three separate measurements using a "dump-and-fill" technique with fresh pellets to ensure an accurate and representative average.
• Determine the relevant color spaces: Choose a shared color space to establish communication throughout the production chain.
• Leverage color quality control software: Ensure your spectrophotometer integrates with or includes built-in color quality control software. This technology allows you to compare the color of your recycled pellets to target specifications or predefined color ranges.

Accurate color matching is essential to creating high-quality products in the textile industry. Image Source: Unsplash user Charisse Kenion

If you work in the textile industry, you understand the complexities inherent to creating the perfect hues. From raw materials to processing methods, the final appearance depends on many variables that you must closely monitor to produce the colors you want. As such, color quality control is vital to product development and manufacturing to help your products live up to your vision.

However, the textile industry faces unique challenges when it comes to implementing robust color quality control systems. One of the most significant is identifying illuminant metamerism, which can be a serious barrier to color matching. Without accounting for this phenomenon, achieving the desired result becomes more difficult, potentially leading to unnecessary waste and reduced efficiency. Investing in technologies that can alert you to illuminant metamerism supports color consistency.

Changes in light source can drastically alter how we perceive color. Image Source: Unsplash user tu tu

Apple’s distinctive boxes serve as a prime example of the importance of color in packaging. Image Source: Flickr user Brett Jordan

One of the most widespread concepts in business is the seven-second rule — people make vital decisions within the first seven seconds of encountering a product, and what happens in that time can either nurture long-term consumer loyalty or turn would-be customers off for good.

However, most consumers’ first contact isn’t with the product, but with its packaging. This element is vital to differentiating your brand and its offerings.

For example, many more people would likely recognize the signature blue of a Tiffany & Co. box than the jewelry it may contain. As such, packaging design is often just as important as the product design, shaping consumer perception from the first touch point. With more products than ever competing for space in the marketplace, smart packaging design choices can be the deciding factor in product success, and spectrophotometric analysis helps ensure that your vision becomes reality.

Harnessing the Power of Color in Packaging

Packaging color choice isn’t arbitrary, and it goes beyond simply selecting an aesthetically pleasing color. Instead, designers must draw on both deeply ingrained color psychology and a preexisting visual lexicon of product associations to create packaging that speaks to the consumer in a language they understand.

Brands use colors to project a specific message. For instance, soft drink brands typically use blue for low-sugar options, green for lemon-lime flavors, and red for cola. Similarly, consumers associate green with pine scent in household cleaners and yellow with citrusy aromas in dishwashing detergent. Packaging also shapes consumer choices in prescription drugs, where it can influence perceptions of quality and performance.

Yet, it's essential to remember how these conceptions can shift over time. The sleek, minimalist, white packaging of Apple products is one that brands often shunned before because it was associated with store-brand or “generic” offerings. It's therefore possible to redefine these perceptions while simultaneously becoming defined by specific color choices.