What Different Types of Colour Spectrophotometers Are There?

As the ideal solution for analyzing sample colour, spectrophotometers are essential equipment for quality, research, and forensic labs worldwide. These powerful devices capture critical data about a substrate's properties to help quantify or categorize it accurately. Spectrophotometers contain a spectrometer, which detects and measures wavelengths using sensors to break down the energy into its components. They also include a light source that emits energy into the sample.

Different types of spectrophotometers exist, each with distinct functions and ideal applications, including colour spectrophotometers that help ensure colour and appearance quality and consistency. These are specialized solutions designed exclusively to measure colour within the visible spectrum between about 360 and 780 nanometers — the wavelengths of light the human eye can perceive. Colour spectrophotometers come in multiple styles and employ different optical configurations to provide precise colour and spectral data.

What Is a Colour Spectrophotometer Used For?

Colour spectrophotometers are invaluable in any application where quantifying colour according to a set of numerical values is crucial to quality and product appearance. Common spectrophotometer uses and industries include the following.

Food and Beverage Manufacturing

Appearance is an important quality indicator in buying decisions, and spectrophotometers help food manufacturers ensure their products fall within acceptable colour expectations to entice consumers. Colour can also signify a food's suitability for safe consumption and influence perceptions of flavor, freshness, and nutrition. Food manufacturers rely on spectrophotometers to quantify chromatic data for products ranging from snack foods to dairy-based items, fruits and vegetables, and edible oils.

Colour plays an equally pivotal role in beverage production, where it helps establish the commercial quality of coffee and the clarity of bottled water according to industry scales.

Plastic Manufacturing

Plastics manufacturers face unique colour challenges as industry regulations evolve. Natural yellowing during virgin production calls for the use of optical brighteners to overcome. With more and more governmental mandates for higher post-consumer recycled content, finding the ideal mix to achieve the desired colour repeatedly is an ongoing issue for most. Colour spectrophotometers help companies in the plastics industry identify and maintain the optimal balance needed for quality, compliance, and appearance.

Chemical Processing

Samples in the chemical processing industry range from opaque powders to translucent or transparent liquids, with some being substantially costly. Accurate chemical mixing is also paramount to safety. Colour spectrophotometers enable professionals in this industry to ensure quality and safety by helping identify physical properties and adhere to strict tolerances.

Other Industries

Additional industries relying on colour spectrophotometers for capturing chromatic and spectral data include:

• Bio-pharmaceuticals
• Building products
• Paints and coatings
• Textiles
• Paper goods

Different Styles and Types of Colour Spectrophotometers

Understanding the differences between implementation style, measurement geometries, and application compatibility can guide you to the ideal solution for your use case.

1. Benchtop Colour Spectrophotometer

Benchtop spectrophotometers are the most versatile, accurate, and popular choices. These are compact models that can integrate easily into a lab setting or onto a bench in the production environment. Many offer the flexibility of both reflectance and transmittal data capture, making them ideal for measuring transparent, translucent, and opaque samples alike.

2. Portable Colour Spectrophotometers

Portable spectrophotometers are models that offer hand-held convenience for capturing chromatic data on the spot. They're ideal for taking measurement capability to a supplier's facility or onto the production floor. They're also perfect for use when sample transport to a lab isn't an option, as when verifying that inventory in stock still meets acceptable tolerances.

Conversely, portable spectrophotometers have one primary challenge. Production floors, inventory storage areas, and supplier sites often have less environmental consistency than is found in controlled quality assurance laboratory settings. More variables in the surrounding area can lead to inaccurate measurements and data discrepancies.

3. In-Line Colour Spectrophotometers

In-line or in-process colour spectrophotometers are designed specifically for direct integration into production lines. Manufacturers create these devices with sensors and technology that can correctly identify the sample while ignoring empty space or production equipment like conveyor belts. Since they allow for continuous, real-time colour measurement without the need to transport samples to a lab for testing, in-line colour spectrophotometers facilitate greater efficiency and productivity.

4.Transmittance Colour Spectrophotometers

Transmittance colour spectrophotometers quantify colour data by directing light through a sample, which will absorb some wavelengths and emit others. Sensors on the opposite side measure the emitted light that passes through. Calculation occurs based on the Beer-Lambert Law to provide a precise transmission percentage.

At least 30% of the source light must pass through the substrate, making this measurement approach suitable only for transparent to translucent solids and liquids. Common applications for transmittance colour measurement include fruit juices, transparent plastic films, and petrochemicals.

5. Reflectance Colour Spectrophotometers

In contrast to transmittance colour spectrophotometers, reflectance colour spectrophotometers measure colour by quantifying the wavelengths that reflect off the sample. These instruments analyze colour and appearance by measuring how light interacts with the substrate based on angles of illumination and reflection. The primary configurations for reflectance colour spectrophotometers are 45°/0° and 0°/45° directional geometry and d/8° diffuse (sphere) geometry.

A directional spectrophotometer shines and collects light from a specific angle relative to the sample. A diffuse spectrophotometer shines and collects light from multiple angles. The first works well for uniform samples, while the second is ideal for rough or irregularly shaped and sized samples.

Reflectance measurement spectrophotometers work with translucent to opaque solids and liquids where no more than 30% of the energy passes through the sample. Typical use cases include quantifying colour in protein products, potato chips, recycled plastic pellets, and mineral powders.

6.Product-Specific Colour Spectrophotometers

Some manufacturers produce specialized colour spectrophotometers for use with specific products and their related colour indices and scales. For example, HunterLab has developed product-specific solutions for accurate colour and appearance measurement in tomato products, coffee, and citrus substrates.

Turn to HunterLab for Colour Spectrophotometers

HunterLab offers an extensive selection of colour spectrophotometers for measuring chromatic, spectral, and appearance data, and our devices represent the most feature-rich and comprehensive solutions on the market. With over 70 years of expertise, we're the industry pioneer in colour measurement science and the most trusted partner for today's leading global brands. Talk to us to find the right option for your application and get a quote online.