What Is a Spectrophotometer and How Does It Work?

While a spectrophotometer might sound like something out of a sci-fi movie, it is actually a powerful tool that companies across the world use to improve their products and learn more about the world. It can tell us if oil is contaminated or if a fruit is ripe. It can also ensure that consistency and performance remain intact across an entire warehouse of products.

So how does all this happen from a spectrophotometer? And how do we use it? The science behind this tool is powerful and can be used in several different ways. To clear things up, we’ve put together some information on the pros and cons of spectrophotometers and how they contribute to different products and technologies, so let’s dive in.

What Is a Spectrophotometer?

A spectrophotometer is a device that precisely measures electromagnetic energy at specific wavelengths of lights. It uses the characteristics of light and energy to identify colors and determine how much of each color is present in a ray of light.The two main components of a spectrophotometer are a spectrometer and a photometer.

  • Spectrometer: The spectrometer uses a lens to send a straight beam of light to a prism, which splits it up into its individual wavelengths. Then, a wavelength selector filters out just the specified wavelengths and sends it toward the photometer.
  • Photometer: The photometer is the part of the device that detects the number of photons that are absorbed, sending that measurement to a digital display.

A spectrophotometer essentially quantifies how much a given substance reflects or absorbs light — something that we tend to think of as more qualitative. You may think to describe an opaque product as red or blue, with a matte or glossy sheen. Spectrophotometers take this evaluation a step further and quantify those characteristics into something that can be measured and used in precise applications, including clinical diagnosis, quality control, product design and biochemical research.

Like all tools, this one has its benefits and drawbacks. Here are some of the advantages of a spectrophotometer:

  • Displays clear, definitive results: With a definite color measurement, differences in viewing circumstances won’t influence the color you work with. For instance, variations in computer screen settings and lighting can make a color appear different than intended. Even differences in human perception, such as color blindness and eye fatigue, can result in many different color interpretations. With a specific measurement, this issue goes away.
  • Quantifies a qualitative characteristic: Since a color sample is precisely defined, you can say goodbye to subjective differences in how people interpret colors. “Maroon” might be an entirely different color to two different people, but they can’t argue with a specific color measurement. This improves communication and makes it easier to discuss your work.
  • Creates consistency: For many applications and brands, consistent color is a vital part of success. A car manufacturer needs to make sure every piece of the body of the car is the same color, and brands need to make sure that all of their marketing maintains consistent colors across mediums. In print and on a screen, it must all look the same. Precise measurements can help them achieve that.
  • Provides incredibly precise measurements: The human eye is surprisingly good at noticing color differences. With precise measurements, you can confidently keep this issue to a minimum.
  • Offers fast operation: Spectrophotometers can gather results in just a few seconds and some models are designed for mass quantities.
  • Comes in various configurations: These tools come in different models for different samples and environments and offer portability, infrared detection and scans of irregular samples.

Some of the disadvantages of a spectrophotometer include the following:

  • It has a somewhat steep learning curve on operating the instrument and interpreting data. Some training may be necessary to fully understand the data provided, though many tasks are easier than others.
  • Not every spectrophotometer can measure all types of samples. You may need a model that’s configured to your needs.

Pricing for spectrophotometers can vary, but you can expect an entry-level product, such as a portable spectrophotometer, to cost less than $9,000, while the high-end options can reach upward of $28,000. Full systems complete with software can exceed $40,000.

How Does a Spectrophotometer Work?

The basic way a spectrophotometer functions is based on the absorption of photons. Higher amounts of photons correspond to higher intensities of light.

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 different colors. The colors of the rainbow follow the progression of energy, with red being the lowest and violet being the highest.

In terms of substances, a sample that absorbs all visible light and doesn’t reflect anything appears black, while a substance that does the opposite looks white. In between those two are substances that reflect certain energies of light and absorb others, displaying specific colors.

Returning to our spectrophotometer, this tool is basically a calibrated light counter.

  • “Spectro” refers to the fact that light is dispersed into individual or groups of wavelengths in the electromagnetic spectrum of energy. Some of that energy is in the ultraviolet and visible light range, which certain spectrophotometers can read, while others can measure infrared radiation. A typical spectrophotometer can measure 31 wavelength bands of light across a 300nm-wide range. More expensive instruments can measure more than 150 bands of light across an 800nm-wide range.
  • “Photometer” in the name refers to the ability to measure the intensity of light at each group of wavelengths and scale it to a range of human perception from 0-100. 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.

By combining these two tools, we can generate specific data about the released colors and associated wavelengths to inform various applications.

What Is a Spectrophotometer Used For?

What Is a Spectrophotometer Used For?Spectrophotometers have more uses than you may think. Research, product development, quality control and diagnoses can all benefit from the data that a spectrophotometer provides.Here are a few specific examples of how these powerful tools are used:

  • Beverages: Color can indicate quality in many beverages from soft drinks and juices to spirits and beer, and consistent color is critical to inspire confidence in customers.
  • Pharmaceuticals: The color of a pill is an integral part of identification. It may not affect its functioning, but it tells people what they’re using. Other pharmaceutical products, like liquid ingredients, have strict standards to meet, some of which involve its color and transparency. Spectrophotometry helps ensure brand colors and identify counterfeit medications.
  • Building products: If a contractor builds a house with mismatched pieces of vinyl siding, the client isn’t likely to be happy with the results. When appearance is involved, color is critical. Many materials also reflect property changes in their color. Anodized metal, for instance, uses a layer of natural oxide to increase its resistance and adhesive properties. Color analysis can confirm that each piece produced reflects these improvements.
  • Chemicals: Chemicals must be clean, consistent in color and free of contaminants to ensure proper functionality and that your customer trusts them. Color is a key part of classifying many chemical products and identifying their composition.
  • Food: Food production uses spectrophotometry in many ways. From evaluating the ripeness of fruits to identifying the appropriate baking contrast of breads and buns, color analysis lends itself to plenty of food-based applications.

These are just a few examples, but you can find spectrophotometers in a vast array of industries and applications, including uses outside of production, like in vital biological research. Other applications include marketing for brands that need to find the most appealing colors for their audiences or improve consistency across materials.

Is a Spectrophotometer Right for Your Application?

If you need to measure colors, consider what it is a spectrophotometer can do for you.

Do you need to do any of the following?

  • Match colors: Ensure your products are consistent in quality each and every time.
  • Detect concentrations: Look for impurities or variations in concentration that could affect the product.
  • Identify product readiness: Measure the extent of specific processes, like oxidization, by checking for specific colors.
  • Conduct product research: Use the color of a product and variations that occur during research to measure its functioning and various characteristics.

Whether you need to research the colorfastness of your textiles, ensure that your olive oil shows optimal health benefits or maintain consistent quality of pharmaceutical pills, spectrophotometers can help. If you’re unsure whether a spectrophotometer would work for your application, reach out to an expert today.

Request a Spectrophotometer Quote

As you can see, spectrophotometers are exceptional tools to have in many settings. They can accomplish several different tasks on a range of product types. These tools can boost your final product’s appearance, improving customer perceptions. They can also influence your production process and the functioning of your product.

At Hunter Lab, we carry a variety of spectrophotometers for samples of all sizes and those that are messy, fluid or bumpy. To learn more about our spectrophotometers and how they can support your work, reach out today and request a quote.

READ  Instrumental Color Measurement Makes the Most of Ammonia Fuming
READ  Understanding Optical Geometries and Choosing the Right Spectrophotometer for Effective Data