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Spectrometers or spectrophotometers are valuable tools companies use to ensure the quality and consistency of the products they make and sell. They can tell us if the oil is contaminated or if the fruit is ripe. They ensure that your favorite tomato ketchup is the same red, batch to batch. They provide the safety and efficacy of the medications you take. They are a valuable tool to ensure corporate brand integrity and that consistency and performance remain intact across an entire warehouse of products. To understand how spectrophotometers work, we need to comprehend the science of spectrophotometry.
Spectrophotometry is the science of how light interacts with matter. The objects we see daily are different forms of matter – solids, liquids, and gases. You may be surprised to learn that matter does not possess color. An apple appears red because of how light interacts with the chemical composition of the apple. When light strikes matter, some wavelengths are absorbed, and some are emitted. We see and perceive the emitted light as ‘color.’
Spectrophotometers mimic this visual observing condition, providing information about the color of materials that is meaningful and actionable, allowing companies to ensure color accuracy and consistency across their range of products and brand colors.
So, how does all this happen from a spectrophotometer, and how do we use it? The science behind this tool is robust and can be utilized in several different ways. To clarify, we’ve gathered information on how spectrophotometers contribute to the color management of various products and technologies, so let’s dive in.
What Is a Spectrophotometer?
You may remember from chemistry class that light is a form of electromagnetic radiation, like microwaves and gamma rays. When we talk about the spectrum of light, we’re talking about a spectrum of energy, where different energy levels create what we perceive as other colors. The colors of the rainbow follow the progression of visible energy, with red being the lowest and violet being the highest. Materials that absorb all visible light appear black, while those that do the opposite appear white. In between those two are materials that emit certain light energies and absorb others, displaying specific colors.
A spectrophotometer is essentially a calibrated light counter.
“Spectro” refers to the fact that light is dispersed into individual wavelengths in the electromagnetic energy spectrum. Some of that energy is in the ultraviolet and visible spectrum, which spectrophotometers can read, while other spectrometers can measure infrared radiation.
“Photometer” measures light intensity at specific wavelengths and is scaled from 0 to 100. Zero equals total darkness, and 100 is perfect white. Some properties, like fluorescence, make it possible for this scale to go over 100, so most spectrophotometers can reach 150 or 200.
Spectrophotometers are used to measure the color of materials. Materials can be solid, liquid, opaque, translucent, or transparent. Different methods are used to measure these materials, depending on their form and transparency. Opaque materials are measured using reflectance spectrophotometers, which measure the amount of light reflected from a sample. In contrast, transparent materials use transmission spectrophotometers, which measure the amount of light that passes through the material. Regardless of the method used, all spectrophotometers share the same basic technology and optical design:
A controlled light source to illuminate the material.
A lens to collimate the light to the monochromator.
A monochromator that separates the light into its constituent color wavelengths.
A wavelength selector.
A detector that quantifies the light emitted from the sample.
Loose powders present several color measurement challenges, from nonuniform samples to light interference. These challenges exist across everything from powdered chemicals to cocoa and baking powder. The ColorFlex L2 overcomes all the challenges of powder color measurement, offering an easy-to-use design and high-quality results.
The Difficulties of Powder Color Measurement
Understanding the challenges faced in color measurement enables you to address them more effectively. Here are the most common issues in collecting spectral data for powders:
Nonuniformity: Powders consist of tiny particles that appear differently depending on how they are prepared.
Light sensitivity: Powders cause light trapping, shadowing, and ambient light interference, which can result in inaccurate measurements.
Sample size: Powders often consist of a small amount of material, but the sample must be thick enough to create an opaque layer.
Fluorescence: Powders are sometimes affected by UV light, which influences their measurement results without adequate controls.
Consumers of food products like tomato paste judge their quality by their color. Appearance relates to freshness and taste, so buyers prefer a product with a standardized, consistent appearance. Following best practices in color measurement allows tomato paste producers to create a product that appeals to customers, influencing sales.
Consider Factors Influencing Color
Before measuring color, determine the factors that influence it. The ripeness of the tomatoes impacts appearance, as the amount of lycopene increases as tomatoes ripen to create a more vibrant red. Other factors, like production methods and storage conditions, lead to variations such as brown or muted hues. Knowing these factors enables producers to adjust their processes based on the measurement results.
While cocoa powder isn't consumed on its own, it flavors and colors many chocolate-based recipes, from brownies to bundt cakes. To ensure their baked goods turn out the way they intend, consumers often judge cocoa powder based on its appearance alone — sometimes subconsciously — to determine its quality.
As a cocoa powder producer, your primary goal is to assure customers that your cocoa powder is the best choice for their recipes. One way to do that is by measuring the color of your cocoa powder at each stage.
In the current era of forensic science, where crime scene materials are accessible in trace amounts, forensic spectroscopy has functioned as a non-destructive alternative to traditional destructive procedures in crime evidence examination.
Through forensic spectrophotometry, analysts can intensely study crime scene evidence using the power of electromagnetic imaging. Spectrophotometry is the process of scientifically and objectively measuring color and radio wavelengths. It is more dependable than using human eyes and provides reproducible results on an easy-to-understand scale. With spectrophotometry, forensic examiners can distinguish between the chemical composition, material, and even brand of a piece of evidence by examining how the sample reflects wavelengths.
Spectrophotometry is a preferred method of forensic analysis due to its non-destructive analytical abilities. This process is versatile enough to analyze fibers, hairs, and forensic materials such as bodily fluids, drugs, and fingerprints. Spectrophotometers also have the advantage of not requiring sample preparation before analysis.
What Is Spectrophotometry?
Spectrophotometry refers to the process of analyzing samples using electromagnetic waves. Spectrophotometers test how the light refracts and reflects off a particular material and investigate its color, infrared and ultraviolet properties, and more. Using spectrophotometry, you can tell the difference between similar samples of hairs, fibers, drugs, bodily fluids, and fingerprints.
Spectrophotometry works by taking a sample and measuring the intensity of light when a beam passes through it. Since each compound transmits and absorbs light differently, it is possible to identify the true nature of a substance by analyzing this wavelength. Depending on the nature of the sample, it can be studied using a UV-visible or infrared range spectrophotometer.
How Is Spectrophotometry Used to Solve Crimes?
Spectrophotometry is a gold forensic analysis standard used by the FBI and the American Hazardous Material Response Unit. The spectrophotometric process is essential for telling apart two nearly indistinguishable samples. Most forensic analysts use UV/vis spectroscopy in forensic science to examine inks and fibers, and thin-layer chromatography is a complementary method.
With spectroscopy in forensics, trace evidence analysis, including hairs, fibers, and glass, is highly accurate. Even samples as small as 10-30 mm fiber can undergo examination to determine their chemical composition and whether they're natural or synthetic. Forensic ink examinations are a perfect candidate for spectroscopic analysis. Wavelength examination can identify the unique hues in inks found at the scene and whether they're similar to specific brands of storebought pens. Spectrophotometry is a non-destructive and safer alternative for identifying inks compared to chromatography.
Spectroscopy has various applications in forensic science, including:
Consumers interpret color consistency as a hallmark of your company's quality and goods' desirability. As a result, color measurement is a critical process in manufacturing across many industries, from food production to plastics and textiles. Spectrophotometers outperform manual comparisons by delivering objective and scientific data that eliminates guesswork and supports consistency. Learning how to choose the right spectrophotometer for your needs helps ensure the most accurate data capture and best value for your investment.
1. Use Your Sample Characteristics as Your Primary Guidance
Modern spectrophotometry is entirely substrate-driven, with specialized solutions available to measure color precisely in samples like tomato products and coffees. As a result, the traits of what you're quantifying color and spectral data in are the bedrock for choosing the right spectrophotometer. Factors to consider include:
Sample Opacity
Spectrophotometers use different measurement geometries and construction designs based on a sample's opacity.
For example, manufacturers generally measure translucent and transparent samples by capturing transmission data. In this design, light passes through the sample to the detectors on the other side, which collect and analyze the data based on the chosen color scale or index.
Directional 45°/0° and 0°/45° spectrophotometers replicate the way human eyes perceive color with either bidirectional or circumferential light source configurations. This approach is best for ensuring color consistency in samples where surface finishes may vary and impact color perception. Diffuse 8° spectrophotometers equally illuminate from all directions with a spherical light source design, making them perfect for applications whose goal is true color match. These solutions are also compatible with transmittance measurement for translucent and transparent samples, boosting their application versatility.
Sample Cost and Size Requirements
When evaluating which spectrophotometer will most effectively meet your needs, the minimum and maximum sample sizes it can handle are a key consideration.
In industries like chemical processing and pharmaceutical manufacturing, samples can be extremely expensive. The ideal solution will offer the smallest possible sample size minimum to help contain costs. In contrast, some applications call for larger samples for increased measurement accuracy, so you'll want to choose a device with the flexibility to accommodate bigger substrate sizes.
The color of crackers can indicate issues that influence flavor and impact consumer perception of products. Measurement offers a standardized method for determining and comparing color and spectral data to improve quality and minimize waste.
Understanding Color Measurement
Color measurement is an objective process that translates color into numerical data. Quantifying color data enables cracker producers to maintain product consistency and quality.
Cracker manufacturers have a unique need for objective data because numerous factors influence customer perception, including:
