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Consistent colour is crucial for plastic products since it impacts brand identity and marketability. Plastic's appearance is based on opacity, texture, and gloss. Every modern manufacturer of opaque sheet plastic must always deliver the correct colour to consumers. 

HunterLab's colour measurement solutions help execute quality control throughout manufacturing processes. 

Factors that Affect the Appearance of Colour

Environmental factors, optical illusions, and surface conditions determine the appearance of an object's colour. Other factors include:

• Subjectivity: Eye sensitivity varies from person to person, causing colour to appear different.
• Light sources: Different types of light, such as fluorescent, incandescent, and sunlight, have different effects on the appearance of colour.
• Surfaces: Surface conditions such as texture and glossiness influence the object's colour.
• Background: An object can appear a different colour against a bright or dark background.
• Surface area: A colour covering a large surface area appears brighter and more vivid than when covering a small object.

Spectrophotometers for the Colour Measurement of Opaque Sheet Plastic

HunterLab offers instruments suited for colour measurement of opaque plastics. Our Agera spectrophotometer caters to opaque plastics like films, sheets, enclosures, and pellets. It measures colour across a spectrum with UV control. Additionally, it incorporates a 60-degree gloss measurement and a 5-megapixel camera to assist with sample positioning.

The effects of moisture on colour measurement are all too real for manufacturers. Wet samples can appear dramatically different from their dry counterparts — darker, more saturated, or with altered surface properties that can cast doubt on result accuracy. This reality creates a dilemma for quality control (QC) teams in many industries. Do you wait for samples to dry and slow throughput, or measure wet samples and risk inaccuracies?

Understanding how sample moisture content can affect colour can help you pivot to a more predictable framework that addresses the variable. With spectrophotometry, you can build reliable measurement protocols that transform wet samples from obstacle into QC advantage.

Why Does Moisture Change a Sample’s Appearance?

Moisture settles into air gaps on a sample's surface, or — in the case of textiles — becomes absorbed by the fibers. Both cases can impact how light interacts with the surface and influence the sample's appearance.

In the simplest terms, wet samples will often appear darker because there is less light scattering and more light absorption. The more moisture-saturated the sample is, the more pronounced the perception shift can become, with highly porous materials often showing the most dramatic effects of moisture on colour measurement.

How Does Moisture Impact Different Materials?

This phenomenon can manifest in different ways in key industries.

Powders and coatings present issues with colour measurement when moisture is present. Structural clumping is a common concern, and the particle aggregation can cause light scattering that impacts appearance. This clumping can also create issues with sample flowability and further impact data consistency and repeatability.

Absorption is the primary challenge with textiles, reinforcing the need for accurate sample preparation. The type of fabric also makes colour measurement more complex in wet samples. For example, cotton and polyester have vastly different absorption capabilities, so colour alterations may appear much more pronounced in one than the other.

What Are the Business Costs of Uncontrolled Moisture Variables?

Uncontrolled moisture variables add measurable costs that affect your bottom line through reduced efficiency, increased waste, and elevated quality risks.

Production Bottlenecks

You know downtime is expensive. When your production line stops to wait for samples to dry for colour measurement, it creates delayed quality decisions and scheduling backlogs. The end result? Throughput and efficiency suffer.

Consider the cascading effects of a single wet sample that requires 30 minutes of drying time. It pushes back every subsequent sample in the queue. Lab technicians stand idle, production managers scramble to adjust schedules, and quality decisions that should take minutes stretch into hours.

The ripple effects extend beyond the lab. Manufacturing lines may continue producing potentially off-spec product while waiting for colour approval, creating inventory that might need reworking or disposal. Meanwhile, shipping schedules slip and customer commitments become harder to meet.

One inconsistent product batch can trigger a cascade of problems — customer complaints, product waste, and costly rework cycles that impact your bottom line. Whether you're measuring colour in paprika or breakfast cereal, particle size variations can compromise brand consistency across product lines.

Measurement inconsistency is only a symptom. The real issue is choosing the wrong spectrophotometer/colorimeter for your specific particle size. Fine spice powders demand different approaches than irregular snack pieces, yet many food manufacturers continue using solutions that weren't designed for their sample's characteristics. Understanding particle size effects on colouru measurement and exploring the best way to address the problems is the first step toward consistent, repeatable results.

What Color Measurement Challenges Do Different Food Particle Sizes Create?

Capturing accurate data in fine powders involves distinctly different challenges than quantifying appearance in snack foods.

When Small Particles Create Big Problems

Finer particles, like spices, seasonings, and powdered flavorings, can form relatively uniform surfaces when properly handled. Yet, achieving that uniformity consistently is where many powder colour measurement programs fail. As samples settle and pack during preparation, surface texture variations often form. Even minor variations affect how light interacts with the material, creating measurement variabilities that have nothing to do with the actual product colour.

For fine particles like these, a 1-inch area of view (AOV) provides sufficient coverage when the sample surface is properly prepared. The key is eliminating operator-introduced errors that cause artificial surface variations. When handling procedures remain consistent across samples and lab operators, you create more predictable measurement conditions.

Large Particle Measurement Pitfalls

Cereals, nuts, snacks, whole beans, and other large or irregular particles create entirely different measurement challenges.

Unlike fine powders that can settle into smooth surfaces, large particles maintain their individual shapes and create voids between pieces. These gaps allow light to penetrate differently depending on how particles settle in the sample container. One measurement might capture more shadow areas, while another captures more direct particle surfaces, leading to inconsistent results.

Surface texture variations in large particle samples further complicate precise data capture. Individual pieces may have curved surfaces, irregular edges, or varying thicknesses, creating shadows and light-reflection patterns that change with each sample presentation. Traditional colour spectrophotometers with a 1-inch AOV designed for smooth, uniform surfaces struggle with these texture variations because they rely on single measurements of limited areas.

Colour is a key indicator of product quality, safety, and efficacy in pharmaceutical manufacturing. As a result, this critical attribute demands precise control to meet consumer expectations and regulatory mandates. Yet, manufacturers must carefully balance colour measurement needs with sterility to preserve safety and hygiene. Many still rely on visual colour assessment, but this method is subjective, hard to track over the long term, and error-prone, increasing your risks of batch rejections and compliance failures.

Understanding the potential costs of outdated measurement approaches and how spectrophotometers/colorimeters address the challenges can help you achieve repeatability and preserve sample integrity.

The High Costs of Uncertainty — and How to Avoid Them

Where visual assessment fails, spectrophotometry excels, helping you build a more reliable quality system.

Visual Assessments Create Risks

Colour measurement in the pharmaceutical industry requires precision that visual methods simply cannot deliver. Human observers often deliver inconsistent results, influenced by their fatigue, colour perception, and environmental variations. These factors make that approach unreliable for the data-driven quality systems pharmaceutical manufacturing demands.

Subjective assessments become potential liabilities where the business consequences may compound quickly:

• Subjective colour data can be challenging to substantiate during regulatory audits or inspections. While some regulatory authorities recognize visual assessment, documentation without objective numerical data could lack the rigor expected.
• Batch-to-batch colour variations that pass visual checks may fail when instrumentally quantified against EP 2.2.2 or USP 1061 standards. That reality can translate into increased batch rejections, costly rework, and expensive API wastage.
• Tracking colour shifts over time with subjective data is an issue. A lack of exact quantification makes it harder to identify patterns before they trigger failures.

Spectrophotometry Is the Best Colour Measurement Solution for Pharmaceutical Manufacturing

Spectrophotometry eliminates the trade-offs. These powerful solutions capture precise, objective colour data while preserving sterility. Unlike visual assessment methods, this equipment delivers numerical colour data that represents objective evidence of appearance. The technology quantifies colour variations that the human eye cannot consistently detect, providing the documentation pharmaceutical quality systems require. This measurement approach also integrates seamlessly with existing laboratory workflows while maintaining the sterile conditions pharmaceutical manufacturing demands.

Safflower oil's versatility brings value to many businesses and consumers. In cooking, it's a viable substitute for frying in vegetable oils since it has a high smoke point. Cosmetics manufacturers prize it for its skin friendliness, while artists prefer it over linseed oil for paint blending.

Consistent colour helps ensure the product meets flavor, quality, and safety expectations, underscoring the need for accurate colour measurement of safflower oil at every processing stage.

What Impacts Safflower Oil Colour?

Factors ranging from natural raw material differences to changes in processing and storage can all impact safflower oil colour:

• Seed coat and petals: A safflower's seed coat and petal colour can alter the colour of metabolites and linoleic acid, producing colour variations in the oil.
• Roasting temperatures: As temperatures rise during roasting, seed colour can transform from pale yellow to golden to a deeper brown.
• Storage: The oil can undergo substantial changes in storage if subject to lighting and air quality differences. For example, extended and excess light or UV ray exposure can bleach safflower oil.

Colour plays a significant role in communicating food quality. Consumers can easily identify an underbaked or overbaked cookie by its abnormal colour and texture, knowing these elements will impact its taste. On the other hand, individuals will associate a perfectly caramelized cookie with a high-quality product that likely tastes great. 

How a cookie looks directly impacts consumer buying habits. You can use a colour spectrophotometer to measure the colour of your cookie samples to ensure they project a consistent and desirable appearance.

Challenges of Measuring Cookie Colour

While measuring cookie colour is vital for producing a high-quality product, this process can pose several challenges to manufacturers:

• Irregular texture: Cookies have many inconsistent characteristics that make colour analysis more difficult, such as their varying shapes, sizes, and highly textured surfaces. To the naked eye, it's nearly impossible to make an accurate colour determination.
• Time commitment: Large-scale cookie manufacturers must analyze thousands of cookies each year. Measuring the colour of cookie samples one at a time can be extremely time-consuming and labor-intensive.
• Equipment wear and tear: Normal wear and tear can impact your colour measurement device's performance, leading to inaccurate measurements. 

High-quality cookie products should be consistent in colour from batch to batch. Image Source: Shutterstock user Natali Zakharova

Few people can resist nibbling on a perfectly-baked cookie. Many find the mouthwatering, nostalgic aromas of caramelized sugar coupled with the rich golden brown crumbles downright irresistible. But if you’ve ever eaten an under or overbaked cookie, you know that not all cookies are as delicious as they should be. Factors like setting the oven temperature too high or too low or baking the cookies for too long or too little time could negatively impact the texture and colour of the cookie as well as someone’s experience eating it.

This is why large-scale cookie manufacturers need to carefully measure the colour of their cookie products. Using a smart spectrophotometer that is capable of accurately measuring the colour of textured samples (like crumbly cookies), you can ensure that every batch of cookies is baked to perfection and that they all appear uniform in colour to your customers. Whether you produce just a few thousand packages of gourmet cookies every year, or you make millions of cookies in a wide variety of flavors and textures, a smart spectrophotometer can help you refine your manufacturing process.

Colour is a Sign of Cookie Quality

The colour of cookies and other baked foods can tell you a great deal about how the product will likely taste. This is due to caramelization and the Maillard reaction, a complex chemical process that causes food to turn brown as it’s exposed to heat.1 During the Maillard reaction, the proteins and sugars in the food are broken down by high temperatures, which results in deeper coloration and a significant change in flavor and aroma. In the case of cookies, the Maillard reaction browns the colour of the raw cookie dough and produces strong aromatic compounds—that classic freshly-baked cookie scent.

For cookie manufacturers, paying close attention to caramelization and the Maillard reaction is important because too much exposure to heat over time could result in an overly bitter, brittle cookie. Likewise, too little heat exposure will impede the development of the Maillard reaction or caramelization, and the cookie will be soft, pale, and somewhat bland in flavor. Customers are aware of the connection between cookie colour, texture, and quality, and the appearance of the cookie may impact a customer’s buying habits.2 This is why you need a smart spectrophotometer to ensure that all of your cookie products have gone through just the right amount of caramelization and appear consistent in colour overall.

Significant variations in cookie colour could be a sign that your industrial oven temperature is set too high or too low. Image Source: Shutterstock user Brent Hofacker