What’s the Difference Between a Spectrophotometer and a Colorimeter?

What’s the Difference Between a Spectrophotometer and a Colorimeter?

A spectrophotometer and a colorimeter are both tools used to measure the color of a product, but what are the key differences between the two? When people hear about these pieces of equipment, they tend to think that they’re interchangeable. Unfortunately, many business owners end up using whichever one their supplier recommends without giving any thought to whether that’s really the best option for them and their business needs.

An Introduction to Spectrophotometers

A spectrophotometer is an instrument that measures how much light is absorbed by a substance at various wavelengths. This means it can be used to find out how much light or energy is passing through something. Some models are handheld, and some are more like huge lab instruments.

They can tell you things about anything from food products to chemicals to drugs—basically anything that absorbs some light as opposed to reflecting all of it, so it’s very versatile! Here we’ll cover what you need to know about spectrophotometers in general, then talk specifically about their two main uses: measuring color or measuring analytical samples.

How does a spectrophotometer work?

A spectrophotometer measures color by measuring how much light is absorbed (or not) at different wavelengths. Most spectrophotometers use a prism to separate light into its component wavelengths, then shine that light through a sample and measure how much of it is absorbed by an electronic detector.

The more light absorbed, the darker your shade of purple. It’s still worth noting that these measurements aren’t necessarily 100% accurate—especially when you start talking about shades lighter than true black—but they are good enough for most applications, including getting quantitative data on dyeing.

An Introduction to Colorimeter

Light is what we use to see, but human eyes can only perceive some of its wavelengths. When you look at something, light enters your eye through a specialized pigment called rhodopsin, which triggers your photoreceptors (rods and cones) to produce an electrical impulse that travels to your brain. In other words, without light, we would not be able to see.

The main role of a colorimeter is measure color or spectra in terms of wavelength using photometric techniques that have evolved over time into various types of instruments depending on their applications such as reflection or transmission analysis.

A simple way of defining them would be as devices that are used for measuring colors and color differences by comparing them with their corresponding standards under specified illumination conditions.

Why use a spectrophotometer over colorimeters in optics labs

The most important thing to remember when choosing between spectrophotometers vs colorimeters is that spectrophotometers can analyze both absorption and transmittance, while colorimeters can only measure reflectance, which limits their applications.

There are many types of instruments for measuring light intensity. While all of these instruments may look very similar, there are subtle differences that distinguish one from another.

Most of these differences deal with functionality. One piece of equipment may be able to do something that another cannot.

For example, one device might be able to measure two wavelengths simultaneously but another device might not have any wavelength selector at all.

advantages of using spectrophotometers over colorimeters

spectrophotometers measure optical density, whereas colorimeters only measure transmitted light. (manufacturers of spectrometers typically don’t include transmittance measurements as part of their standard test) As such, spectrophotometers are more accurate because they detect specific wavelengths over an absorbance spectrum.

This allows them to produce a wider range of analyses than that of colorimeters.

Similarities between colorimeter and spectrophotometer

Both devices analyze colors to create quantitative data. They both analyze light entering through an opening, although colorimeters are usually built for portability and therefore might be hand-held or free-standing instead of fixed in one place like spectrophotometers.

Furthermore, spectrophotometers use prisms or diffraction gratings to separate white light into different wavelengths of color that can then be measured individually; however, colorimeters use filters to divide up visible light.

Both instruments have many uses in quality control and industrial processes, but they are typically used differently because they measure different parameters.

Let’s take a look at how each device works:

One common measurement taken by spectrophotometers is absorbance, which is simply the amount of light absorbed by whatever you’re measuring.

A second measurement taken by these instruments is transmittance, which is exactly what it sounds like—the amount of light transmitted through whatever you’re measuring.

As you may imagine, it would be difficult to make precise measurements if there was interference between your samples and your instrumentation.

To prevent such problems from occurring, we can calibrate our spectrophotometer using standard solutions—often called primary standards.

These solutions contain pure compounds with known concentrations so that we know how much sample we need to take in order to get accurate results.

When should you use this instrument

A spectrophotometer measures light, while a colorimeter measures color. So what’s their primary use? Both are useful in industrial settings where there is an interest in quantifying or analyzing light, but they’re particularly useful for textile manufacturers as well as painters.

They can also be used to measure material properties such as color stability and water purity. The choice between these two instruments depends on your specific needs.

For example, if you want to analyze multiple samples at once, you might opt for a spectrophotometer. If you need high-precision measurements of one sample at a time, then it might make more sense to go with a colorimeter.

Is there anything better than this device?

Nothing seems to make life easier than being able to accurately measure color, while spectrophotometers are made specifically for that purpose.

But what is it exactly, and how does it differ from a colorimeter? These are two of our most frequently asked questions at X-Rite, so we thought we’d take some time to shed some light on these products. It might be best to say these devices really aren’t all that different in application or principle – but their intentions are very different.

Are there any alternatives to this device?

Instead of buying both a spectrophotometer and colorimeter to do your job, why not pick one device that does it all? While there are some similarities between these two devices, each has unique features. Check out an optical density meter if you’re interested in just one multi-purpose tool.

With an optical density meter, you get color measurements as well as absorbance values from just one device.


With so many different instruments on our lab bench, it’s easy to get confused as to which one is best for which application.

Colorimeters are great for accurately quantifying how much color is in a solution. They’re also useful for determining if solutions are within an acceptable range of color (e.g., natural solutions). But, they aren’t as sensitive as spectrophotometers at measuring low concentrations of color and can be hindered by low reflectance samples.

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