What Is Colour Stability and Why Is It Important?

Colour is one of the first sensory processes humans experience. It can alert us to potential danger, like the orange of a safety cone, or tell us what flavor we might expect from a piece of candy.

Long-term changes to colour appearance can have negative impacts — a dusty pink fire engine isn't going to draw attention as effectively as a bright red one. Learning about colour stability and understanding its importance, challenges, and the best way to ensure it can help you prevent unwanted deviations from the intended, expected, and desired results.

Defining the Stability of Colour

In its simplest terms, colour stability refers to how well a material can maintain a consistent colour throughout its life span. 

It's important to note that colour stability substantially differs from colour consistency and constancy. While maintaining those traits is also vital, these terms refer more to eliminating chromatic variations across batches, production lines, facilities, and observation conditions like illumination.

Factors That Can Impact Colour Stability

Multiple factors can cause alterations in chromaticity as time passes. As a result, changes can arise during any manufacturing stage and throughout material storage and distribution. Excess exposure to the following can impact colour stability:

• Moisture
• Oxygen
• Light and UV rays
• Extreme temperatures
• Chemicals

The Importance of Colour Stability

Maintaining colour over time is vital for several reasons.

Quality

Colour and quality are inherently intertwined. Chromaticity that meets a consumer's expectations encourages them to form a positive brand image. When colour conforms to industry standards, it also showcases your company as one committed to best practices. Colour stability helps support these outcomes by ensuring long-lasting durability, which boosts perceived value.

Safety and Compliance

In many products, colour stability goes hand in hand with safety. Consider goods like reflective safety tape, camouflage military uniforms, and edible oils, where colour alterations over time can impact visibility or indicate potential contamination that would make it unsafe for consumption. Additionally, products whose colour maintains acceptable tolerances in highly regulated industries prevent unnecessary fines or penalties.

Appeal

Customers may see colour as the primary determinant in their purchasing decisions for certain items, like vinyl siding and roofing shingles. Remodeling a home exterior is a significant investment that consumers expect to last for years. Customers don't just want it to look good now — they want to know the colour they see at first is the colour they can expect it to stay, even after long-term exposure to the elements. 

Common Applications and Challenges of Colour Stability

Colour stability is instrumental in many modern applications and presents unique challenges for each.

Food Production

Consumers may forego an item if its appearance varies from expectations. For example, meat that looks grayish brown rather than red can signal contamination or spoilage. Food manufacturers require scientific methods for assessing colour stability and how storage, transport, and production can affect it.

Plastic Manufacturing

Plastic manufacturers face multiple challenges with colour durability since some yellowing occurs in virgin production. Overcoming yellowing requires optical brightening agents in addition to the other components needed for successful production, like O2 scavengers and heat additives. All can affect plastic colour stabilization, cementing the importance of identifying and precisely recreating the optimal mix.

Dental Components

Maxillofacial reconstructions and dentures deliver life-changing self-confidence — when the colour is natural and stays that way. These products are subjected to many environmental stressors, including cleansing chemicals and colour-saturated foods and beverages. Those manufacturing composite resins and silicone polymers for dental applications need reliable methods for evaluating colour during and beyond production to meet patient expectations.

Pharmaceuticals

Colour stability in pharmaceutical manufacturing is essential for safety, efficacy, and compliance. Medications and compounds that undergo colour changes during production, storage, and distribution could be less effective or contaminated. Pharmaceutical manufacturers that adhere to strict colour measurement protocols better uphold drug quality and integrity and comply with regulations.

Paper

Colour stability is critical in applications like printmaking, where a paper's ability to retain the desired chromaticity is essential to long-term appeal. Paper manufacturers frequently depend on advanced technology solutions to evaluate how exposure to factors like heat, moisture, and UV light impacts colour durability over time so they can adjust their strategies to improve stability.

How to Improve Colour Stability

Fortunately, there are ways to improve colour stability to ensure your goods uphold quality, safety, conformance, and appeal.

Control the Quality of Your Inputs

Establishing strict quality assurance controls for all your inputs is the ideal starting point, as inferior raw materials can substantially influence colour stability. For example, pigments with inconsistent colour and low-quality colour stabilization additives may degrade faster. Similarly, colour stability in frozen meat products starts with using high-quality proteins that are as fresh as possible.

Measure at Every Stage

Quantifying spectral and chromatic data at every manufacturing stage is the best way to ensure colour stability since exposure to altering factors can happen at any point in the product life cycle. Businesses should implement measurement protocols during manufacturing, while in storage and distribution, and in testing labs that can simulate real-world conditions.

For example, textiles like denim may fade with repeated washing. Manufacturers can subject their denim goods to multiple wash cycles to evaluate colour stability over time. Capturing data at each stage can help these organizations pinpoint the best colour stabilizers and refine their processes for maximum colour durability.

Use the Best Colour Measurement Solution

Colour spectrophotometers are a powerful solution for capturing spectral and chromatic data accurately, objectively, and scientifically. These specialized devices measure colour by evaluating lightwaves within the visible spectrum — those ranging between 400 and 700 nanometers. They're designed for precision readouts with specialized optical configurations that measure colour through reflectance or by quantifying lightwave transmittance.

Beyond accuracy, spectrophotometers offer other benefits, like:

• Versatility: Options are available to conserve bench space with compact models, integrate directly into production lines, or capture data with a hand-held solution. This flexibility makes them perfect for many colour measurement workflows.
• Nondestructive measurement: These devices don't damage the underlying substrate they're measuring, contributing to less waste. Additionally, solutions with a no-contact design help safeguard against potential cross-contamination.
• Value: Spectrophotometers can simultaneously quantify additional data instrumental in product safety, appearance, and appeal, such as haze measurements. 
• Speed: Many spectrophotometers offer precise data in just a few seconds with one-touch measurement.

Improve Your Product Quality and Colour Stability With HunterLab

HunterLab has been modern manufacturers' partner of choice for colour measurement science for more than 70 years. Our high-quality spectrophotometric solutions enable producers in many industries to ensure colour stability through accurate readouts that support fewer colour variations over time.

Find the ideal device for your application online, or reach out to our experts for advice on identifying the best one for your needs.