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Color surrounds us every moment of our lives and affects our emotions, behaviors and beliefs in large and small, conscious and unconscious ways. Color can set a mood, warn us of danger, give us critical information and even bring us joy. Despite the universal presence of color, describing it remains elusive, in part due to variations in color perception from person to person and in part due to a lack of descriptors for each of the millions of shades seen by the human eye.

Instrumental color measurement moves beyond the limits of human perception and vocabulary and allows us to capture color information as objective data, creating a common language of color that is essential for communication within and between industries around the world, ranging from food and beverage to pharmaceuticals. The two most advanced color measurement instrument types are colorimeters and spectrophotometers, both of which use sophisticated technologies to accurately and precisely quantify and define color.

While closely related, these instruments have unique qualities that may make one more suitable than the other for a particular type of measurement. Understanding the characteristics of a colorimeter vs. spectrophotometer can help you select the best tool for your application.

What Is a Colorimeter?

A colorimeter is designed to perform a type of psychophysical sample color analysis, which means its measurements correlate to human color perception. In other words, it is designed to see color the way we do.

Its results are direct and read as tristimulus values. A tristimulus value is one that identifies a color with characters that represent different dimensions of its visual appearance. A tristimulus value may contain values like X, Y and Z or L, a and b. The “gold standard” for tristimulus colors is the CIE Color System, developed by the International Commission on Illumination — the CIE in the title stands for the French version of their name.

There are a few unique components involved in a colorimeter.

• Illuminant: The illuminant represents a specific light source, such as daylight or incandescent light, to project consistent brightness onto the object. In a colorimeter, an illuminant is fixed.
• Observer: The standard observer offers a specific field of view with which to analyze the colors. A colorimeter usually uses a 2-Degree Standard Observer, which is suitable for color evaluation and quality control.
• Tristimulus absorption filter: The absorption filter isolates specific wavelengths to be applied to the sample.

Types of Colorimeters

Colorimeters are essential in determining color objectively and accurately. Their different varieties measure color to varying depths and degrees. Types include:

• Densitometers: These measure the darkness level, or density, of semi-transparent material.
• Photometers: Color photometers measure how color is transmitted and reflected.

How Does a Colorimeter Work?

A colorimeter’s usage is often based on the Beer-Lambert law, which tells us that the concentration of a solute is proportional to its absorbance. The colorimeter starts with a simple light source. With the help of a lens and tristimulus absorption filters, the beam of light becomes a single, focused wavelength which then moves through to the sample solution. On the other side of the solution is a photocell detector that identifies how much of the wavelength got absorbed. The detector is connected to a processor and digital display that offers a readable output of the results.

Now that you know how it works, let’s take a look at the pros and cons of a colorimeter.

Modern color measurement technologies go beyond the subjective human gaze and allow us to objectively quantify a rainbow of colors. Image Source: Unsplash user Denise Chan

Color surrounds us every moment of our lives and affects our emotions, behaviors, and beliefs in large and small, conscious and unconscious ways. Color can set a mood, warn us of danger, give us critical information, and even bring us joy. Despite the universal presence of color, describing it remains elusive, in part due to variations in color perception from person to person and in part due to a lack of descriptors for each of the millions of shades seen by the human eye.

Instrumental color measurement moves beyond the limits of human perception and vocabulary and allows us to capture color information as objective data, creating a common language of color that is essential for communication within and between industries around the world. The two most advanced color measurement instrument types are colorimeters and spectrophotometers, both of which use sophisticated technologies to accurately and precisely quantify and define color.

While closely related, these instruments have unique qualities that may make one more suitable than the other for a particular type of measurement.1 Understanding the characteristics of a colorimeter vs. spectrophotometer can help you select the best tool for your application.

Colorimeters are ideally suited for evaluating final color results and identifying unwanted color variations. Image Source: Pexels user Karolina Grabowska

What Is a Colorimeter?

A colorimeter is designed to perform a type of psychophysical sample analysis by mimicking human eye-brain perception, which means its measurements correlate to human perception.. In other words, it is designed to see color the way we do.

Its results are direct and read as tristimulus values. A tristimulus value is one that identifies a color with characters that represent different dimensions of its visual appearance. A tristimulus value may contain values like X, Y and Z or L, a and b. The “gold standard” for tristimulus colors is the CIE Color System, developed by the International Commission on Illumination — the CIE in the title stands for the French version of their name.

There are a few unique components involved in a colorimeter.

• Illuminant: The illuminant represents a specific light source, such as daylight or incandescent light, to project consistent brightness onto the object. In a colorimeter, an illuminant is fixed.
• Observer: The standard observer offers a specific field of view with which to analyze the colors. A colorimeter usually uses a 2-Degree Standard Observer, which is suitable for color evaluation and quality control.
• Tristimulus absorption filter: The absorption filter isolates specific wavelengths to be applied to the sample.

At my new quality assurance job, one of our product quality checks is to measure the color of our product and to ensure that we are producing our product that is within a preset acceptable color range. We use an instrument, a spectrophotometer, that reports Hunter L, a, b; XYZ, and L*a*b scales. I’ve always thought that color was measured in terms of RGB, like the way computer monitors and TV screens describe color. I’ve even created custom colors for fonts on my computer by manually adjusting the RGB quantities. Can someone explain why we would measure color using Hunter L, a, b; XYZ, and L*a*b instead of RGB?

It depends on what you want. Do you want White, Yellowish White, or Bluish White?

In simple terms, the primary difference between CIE Tristimulus Scales (Hunter L, a, b; XYZ, and L*a*b scales) and RGB is their purpose within the color world. RGB is a device dependent method of producing color and is not exact enough to be used to describe a color for quality control purposes. CIE XYZ color scales represents the true color of an object, while RGB describes a flat solid color representation of the average color of an object is displayed on a screen. One is used to provide color directionality (RGB), the other is used to precisely quantify a color (Tristimulus values). let’s illustrate…

Let’s take a drive to the Lincoln Memorial

Let’s pretend the Lincoln Memorial is not a physical object but rather a specific color, let’s say white, since in fact it is made of a very specific white concrete. To get there, should I use RGB or Tristimulus values? This will depend on how close to the Lincoln Memorial, or its specific color of ‘white’ you want to get. Using RGB to measure the color white and expecting analytical precision would be like trying to get to the Lincoln Memorial without the exact address and a GPS/map to guide you. While you may know that the Lincoln Memorial is located in Washington D.C., getting to the specific address would be a challenge.

RGB is very much like this in that you might know the general area of red, blue, green, or in this case ‘white,’ but getting to a precise color takes more than a general direction. Much like GPS, which uses three-dimensional physical coordinates that can guide you to within three feet of the desired address, CIE Tristimulus scales provide three-dimensional color coordinates to give you the exact address of a specific color with extreme precision. While RGB might drop you off on the Mall without any further direction, tristimulus coordinates will direct you precisely to a specific color with decimal precision, much like GPS will guide you to the Lincoln Memorial within three feet.

“Amber beer” is a catchall term that refers to any medium-opacity beer, ranging from bright red to caramel brown in color. Image Credit: Unsplash user Julia Nastogadka

I used to believe that all amber beer looked about the same: a bold, almost cranberry-colored brew with a hint of frothy, cloudy opacity. Everything changed for me when I went to my first amber beer tasting. I saw a long tasting table lined from end-to-end in every amber style imaginable, from the bright red ale that I was used to seeing, to the deep caramelized browns of American amber ale. It was clear that the brewers were proud of their glasses — each ale had an unmistakable color unlike any other sitting next to it. When I looked closely at each glass, side-by-side, I could see the subtle differences between them. I saw flecks of gold in one light red beer, whereas its neighbor had deeper, almost rose-like color qualities.

These subtle differences in color and opacity make your brew absolutely unique. That’s why it’s important to measure your amber beer’s opacity and color consistency throughout the brewing process. When it comes to red or amber ale, your color is your signature, and it will keep your customers coming back year after year.

Brewers often find it difficult to measure their amber beer’s color by eye, since this beer style has a wide range of possible color variations. Image Credit: Pixabay CC user PeterKraayvanger

To help photographers and videographers realize their vision, lens filters must be consistent in color and free from contaminants. Image Source: Shutterstock user Layue

Colored lens filters are essential tools for photographers and videographers. These accessories improve the quality of their images and help them achieve the aesthetic they are seeking to create, expanding both technical and creative boundaries. However, this can only happen when the color of the lens is consistent and the product is free of contaminants such as dust or other types of flaws in the glass. If the lens is too hazy or the color is too light or dark, it could compromise the quality of the final image. To prevent this, manufacturers of colored lenses must rigorously test their products for color consistency and clarity throughout the production process. When you perform color quality control tests throughout your manufacturing process, you’ll ensure the integrity of your products, refine your production processes, and help your customers realize their artistic visions.

The Importance of Color Consistency and Clarity in Lens Filters

Different lens filters have very specific uses in photography and videography and are sought out to create unique effects that are not possible with conventional lenses. But if the filter is off in color by even a few subtle shades, it could significantly impact the image’s appearance. This is why color consistency is critical for lens filter manufacturers to achieve.

For example, UV filters for cameras are typically clear, but filters that contain a heavier coating of UV filtration will start to look amber in color.1 In fact, if you want your product to filter out as much UV light as possible, your filter should appear fairly dark. If your filter appears almost colorless, however, it may be a sign that you haven’t coated the filter properly and the level of UV protection may be diminished. This can significantly impact the functionality of the filter and create unwanted—and unappealing—color shifts. For example, on a sunny day when the camera is exposed to a great deal of UV light, a blue haze may appear in the final image if UV light is not properly filtered out. Similarly, skylight filters are typically pink in color because they counterbalance the blue bias that film stock typically has. However, this requires a delicate balance; if your filters are too pink, they will make all of the blue tones in the image disappear, whereas if the filters aren’t pink enough, they won’t effectively counterbalance the blue tones in the film. This is why it’s important to get the color just right on your lens filters.

Unfortunately, achieving the right lens color can be difficult, as you must dye the lacquer the same color from batch to batch and you also apply this lacquer in a consistent layer to create the colored film. If you fail to dye the lacquer properly or you apply the lacquer in uneven layers, it could cause the color of the lens filter to appear inconsistent. Additionally, haze and contaminants in the glass can impact the appearance and functionality of the product. For instance, if you use thick glass, you’re much more likely to have air bubbles or other flaws in the product that will show up on film. If you use colored polarizing filters (made from plastic) that you place between two layers of glass, contaminants may come between the glass and the colored film, resulting in a permanent flaw. Other factors like improper formulation and even the oils from your hands can make the lens filter appear hazy. This cloudiness, regardless of the source, will have an effect on the final image; the unwanted particles in the lens will scatter the light when it hits the lens’ front element, and this could cause a stray lighting effect or result in a blurry image.2

To ensure that your lens is manufactured correctly, you should test your materials for color and clarity throughout the manufacturing process. Using a spectrophotometer, you can ensure that the color of your lenses is consistent from one batch to the next and that your glass is free of any potential contaminants.

What happens when the blue on Line A doesn't match the blue on Line B? Or when today's production run doesn't match yesterday's? In manufacturing, consistency equals quality. Nowhere is that more visibly evident than in your product color, where consumers will immediately notice any discrepancies. As you scale production across lines that span different facilities — and sometimes even continents — ensuring color harmony can become increasingly complex.

Understanding the importance of consistent color, knowing the challenges to achieving it, and learning how you can attain it can help you develop effective color-control strategies for your production processes.

Why Is Color Consistency Critical?

Inconsistent color has real-world impacts on your brand reputation and bottom line. When color is repeatable and consistent, you benefit from:

• A better brand perception: Customers have fewer reasons to question your quality or your product's desirability, flavor, freshness, and safety. 
• Fewer rejects and less rework: Goods that meet your customers' color specifications and expectations are less likely to result in costly rejects and rework, saving you time, money, and resources.
• Higher conformance with industry standards and regulations: Certain products and industries have strict color standards or regulations, such as pharmaceuticals and food dyes. Consistent color helps ensure your goods conform to the required frameworks and meet safety requirements.

What Are the Challenges of Achieving Consistent Color?

When production scales across multiple lines and facilities, several key challenges to color consistency arise:

• Raw material variations: The color and quality of raw materials often vary, especially when suppliers differ due to geographic location, availability, or supply chain diversity. Batch-to-batch inconsistencies also frequently occur in the plastics industry, where dynamic concentrations of recycled polyethylene terephthalate (rPET) in raw materials can dramatically impact final appearance.
• Influences in the production environment: Facilities may experience different environmental conditions, from humidity to heat and more, that can contribute to color alterations. Equipment may also vary widely and cause color inconsistencies.
• Variations in process parameters: If facilities differ in their production workflows, methods, or techniques, color consistency becomes more challenging. For example, variations in key process parameters like time and temperature will lead to differing color outcomes.
• Outdated color assessment approaches: Relying on antiquated measurement techniques like visual color comparison increases the potential for inconsistencies. This approach is too subjective, unreliable, and error-prone to uphold consistency effectively.

Safflower oil's versatility brings value to many businesses and consumers. In cooking, it's a viable substitute for frying in vegetable oils since it has a high smoke point. Cosmetics manufacturers prize it for its skin friendliness, while artists prefer it over linseed oil for paint blending.

Consistent color helps ensure the product meets flavor, quality, and safety expectations, underscoring the need for accurate color measurement of safflower oil at every processing stage.

What Impacts Safflower Oil Color?

Factors ranging from natural raw material differences to changes in processing and storage can all impact safflower oil color:

• Seed coat and petals: A safflower's seed coat and petal color can alter the color of metabolites and linoleic acid, producing color variations in the oil.
• Roasting temperatures: As temperatures rise during roasting, seed color can transform from pale yellow to golden to a deeper brown.
• Storage: The oil can undergo substantial changes in storage if subject to lighting and air quality differences. For example, extended and excess light or UV ray exposure can bleach safflower oil.