Spectrophotometers Aid Plant Identification and Botanical Research
plant identification
Many new species of plants are identified each year, and color serves as an important differentiator. Image Credit: Unsplash user Chris Lee

In 2016 alone, 1,730 new species of vascular plants were discovered.1 While that may seem like a large number, it pales in comparison to the total number of known species, which is on the order of 400,000.2

The sheer number of plants makes categorization essential. Of the many characteristics by which we categorize our plants, color is one of the most immediately apparent, and therefore most important. But, of course, your information is only as good as your measurements. The human eye sees color subjectively, which creates issues for scientists attempting to create an objective catalog of plant color. For accuracy and the ability to create a meaningful comparison, it’s necessary to rely on a digital instrument such as a spectrophotometer.

Color an Important Tool in Plant Identification

There are many important reasons to be able to distinguish between similarly colored plants. Botanists in the field can turn to color identification to differentiate otherwise similar vegetation or to help identify a new species. Rose breeders and other floriculturists keep a close eye on color in order to improve their husbandry practices, select appropriate flowers for various uses, and distinguish between species of wildflowers. Food processors, such as saffron producers and distributors, can use color to detect supply adulteration. Land managers may rely on color identification to detect invasive species or promote the growth of endangered ones, as well as for simple surveys. Foresters rely on color, among other factors, to differentiate between similar species of trees and other forest vegetation.3

plant identification
Color is can be used to distinguish trees in a forest. Image Credit: Unsplash user Noah Silliman

The Limits of Vision-Based Identification Based on Color Charts

A number of vision-based identification methods have been developed over the years to aid botanists and other professionals who need to identify plants by their color. These methods rely primarily on matching plant color to a standardized color chart. For decades, these charts played a valuable, in imprecise, role in plant identification. However, vision-based plant identification based on color charts is an inherently unreliable method of assessment for a number of reasons:

  • The human eye lacks the ability to distinguish fine shades of color beyond a certain point. While the color charts may provide a rough framework for identification, there are only so many shades they can represent, and human observers must turn to guesswork to identify colors which do not match exactly.
  • Human perception of color is a highly variable, depending factors such as biological and cultural influences.
  • Environmental influences such as background colors and  lighting conditions can have a dramatic impact on color perception. As such, observers attempting to match colors under different environmental conditions will be prone to error; plants that appear one color in the field may appear a different color in the laboratory or even under different weather conditions or at different times of day.
  • Color charts themselves are vulnerable to variability, as their colors can shift or fade over time, and charts printed by different manufacturers may not be in exact agreement.

Taken together, the imprecision of vision-based color matching renders objective, instrumental comparison necessary.

plant identification
The brilliant hues of Autumn can be captured with a spectrophotometer. Image Credit: Bernd Schulz

Spectrophotometers Offer Accurate and Precise Color Measurement

Spectrophotometers are able to overcome the shortcomings of vision-based assessment of printed color charts with digital precision. These advanced instruments analyze color in more granular detail than the human eye, allowing them to discern between nearly identical shades with ease and distill chromatic information to objective data. This is possible in part because spectrophotometers use controlled bursts of light to measure samples, meaning that they generate generate accurate and precise results in any environment. Depending on the geometry of the instrument you are using, you also have the option to account for the effects of gloss and texture, which can be useful in identifying rough or oily plants. As such, instrumental measurement ensures that geometric features do not interfere with accurate color determination.

Spectrophotometric technologies represent a significant improvement over older, less precise visual inspection methods, augmenting your ability to correctly identify and classify botanical material. In fact, vision-based plant identification based on color charts seems out of step in our technologically advanced world.

The HunterLab Difference

With over six decades of experience designing spectrophotometers for industrial and scientific applications, HunterLab has developed a reputation for unparalleled color measurement excellence. Our spectrophotometers produce rapid, accurate, and repeatable results regardless of environment, and our portable spectrophotometers are durable enough to endure tough field conditions. Contact us today to learn more about our renowned technologies and let us help you select the perfect spectrophotometer for your research needs.

  1. “New Plant Discoveries”, 2017, https://stateoftheworldsplants.com/2017/new-plant-discoveries.html
  2. “Plant Species Numbers”, http://www.bgci.org/worldwide/1521/
  3. “Tree Identification Keys for Member Trees”, 2017 https://www.arborday.org/members/treeIDKey.cfm
Rating Maple Syrup With Spectrophotometers Helps Producers Make the Grade
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Maple syrup in the comb of a waffle. Image Credit: Unsplash user nabil boukala

Growing up in New England, I was raised to pay attention to my maple syrup. We were allowed to eat as much “table syrup” as we liked, but when it came to the real stuff—the good stuff—we had to ration and apportion each perfect drop. When we were able to use it on our pancakes, waffles, or french toast, we were over the moon. We’d carefully drizzle the sticky bottle over our dishes, savoring each bite so long our meal would be cold by the time we were done. To this day, when it comes time for me to buy maple syrup, only the real thing will do.

Maple Syrup Grades Assigned By Color

Of course, not all maple syrup is the same. Maple syrup exhibits a wide range of color, turbidity, viscosity, and flavor, depending on the properties of the raw maple sap and the particularities of processing. Some are dark and stormy, like a blizzard on the mountain, while some are so light and airy they seem to be the food of angels.

For many years, maple syrups were classified and graded according to United States Department of Agriculture (USDA) color standards, with a significant bias toward lighter syrups. Lighter syrups were grade A, while darker syrups were relegated to grade B. This created a consumer perception that lighter syrups were preferable to darker syrups.

While this color-based grading system was voluntary, not mandatory, it nonetheless created difficulties for manufacturers of darker syrups. This resulted in multiple deleterious effects, including the reduction of manufacturer revenue. Grade B syrups, regarded as inferior, could not sell for the same price as grade A syrups, reducing the amount of yield each manufacturer could glean from their harvest.

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Maple trees display their fall foliage. Image Credit: Unsplash User Dennis Buchner

The Reinvention of Maple Syrup Grading

Thanks in part to the efforts of the International Maple Syrup Institute, a non-profit society dedicated to the maple syrup industry, the USDA changed their grading system in 2015 to describe maple syrup without creating a bias. 1 . The new classifications for color are:

  • U.S. Grade A Golden (delicate taste, ≥75.0 percent light transmittance (%Tc))
  • U.S. Grade A Amber (rich taste, 50.0-74.9%Tc)
  • U.S. Grade A Dark (robust taste, 25.0-49.9%Tc)
  • U.S. Grade A Very Dark (strong taste, <25.0%Tc)

As you can see, these new standards classify even “Very Dark” syrups as grade A, increasing their value to manufacturers and broadening the palates of consumers. While different syrups may have different uses and appeal to different customers, all grade A syrups are of the highest quality. Only syrups which have been damaged or contain off flavors or odors are classified as grade B under the new standards.

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Maple syrup on pancakes. Image credit: Unsplash user Herson Rodriguez

Using Spectrophotometers to Assess Maple Syrup Color

The earlier standards relied on color grading kits supplied by the USDA to determine maple syrup color. Manufacturers would receive physical color samples from the agency and match their syrups to the standards. This presented many problems with accuracy. Depending on lighting conditions, maple syrup can appear to be different colors. This is because, as a translucent liquid, its color is a function of the light transmitted through it, in combination with the light reflected off of it. So, under different lighting conditions, a manufacturer, a regulator, and a consumer could perceive the same sample of maple syrup as being different grades. Additionally, inherent variation in human sight can cause significant differences in color perception and lead to inaccurate grading.

With the improvement of the grading system came improvement of measurement systems. Now, spectrophotometric measurement is required to assess the color of maple syrup and determine its grade. According to the USDA regulations:

The four color and flavor classes of maple syrup will be determined by using a spectrophotometer that provides a measure of percent of light transmission using matched square optical cells with a 10 millimeter (mm) light path at a wavelength of 560 nanometers (nm), with the color values expressed in percent of light transmission as compared to analytical reagent glycerol fixed at one hundred percent transmission, and symbolized by %Tc values; or by any method that provides equivalent results.

Spectrophotometers can rapidly assess the color of maple syrup and assign it a value on the appropriate scale. Better yet, spectrophotometers can indefinitely replicate the same lighting conditions for each measurement. This guarantees that syrups graded on this scale will all be measured to the same standard, reducing mislabeling and miscommunication.

The HunterLab Difference

Having worked closely with the maple syrup industry, HunterLab uses industry experience and knowledge to design superior spectrophotometric instrumentation for maple syrup measurement. HunterLab spectrophotometers are fast, reliable, and easily integrated in production lines . By using a HunterLab spectrophotometer, your maple syrup operation will be able to accurately and efficiently assign the appropriate grades your products regardless of operator. To find the spectrophotometer that’s ideally suited for your needs, contact us today.

  1. “United States Standards for Grades of Maple Sirup (Syrup),” 2015, https://www.regulations.gov/document?D=AMS-FV-15-0006-0001
Spectrophotometers Help Orange Groves Produce Ideal Juicing Oranges
juicing oranges
Growing conditions can significantly impact the color of juicing oranges. Image Credit: Unsplash user Brian Jimenez

When you own an orange grove, your money actually does grow on trees. If you’re lucky enough to be in the orange business, this means it’s very important to know the best ways to keep your trees producing the highest quality oranges possible. What is the ideal soil mix? Which minerals and nutrients should be fed to the trees roots, and in which proportions? At which temperature and humidity levels is it necessary to test for infestations? There are many variables that must be measured and weighed against each other, all for the purpose of knowing the answer to a simple question: what makes my oranges grow the best? By using a spectrophotometer to assess the color of oranges and studying the factors that contributed to the development of their color, it’s possible to obtain an answer.

juicing oranges
Research reveals that the color of orange juice affects consumer’s perception of its taste. Image Source: Unsplash user JÉSHOOTS

Color Affects Taste Perception in Orange Juice

Before we explore how spectrophotometers can help you determine your ideal growing processes, it’s important to define what is meant by the best. In the case of juicing oranges, quality is often perceived through color. This is because color is a primary indicator of customer preference and can even alter perceptions of taste. As discovered in a study published in the Journal of Consumer Research, while brand and price information had no effect on consumer taste perception, the effect of color was significant.1  In fact, the effect of color even stronger than the effect of taste. According to the study:

Given two cups of the same Tropicana orange juice, with one cup darkened with food coloring, the members of the researcher’s sample group perceived differences in taste that did not exist. However, when given two cups of orange juice that were the same color, with one cup sweetened with sugar, the same people failed to perceive taste differences.

From this, we can assume that orange groves which produce the most desirably colored oranges will be the most successful if other factors are equal.

Refining Agricultural Practices

The orange color in oranges and their juice is produced by organic pigments the orange creates called carotenoids.2 These are the same pigments found in carrots and butternut squash. Different environmental factors affect the production of carotenoids in oranges in different and intermingling ways. By measuring the color of oranges produced in different areas within the same grove—or different groves across the state, nation, or world—and correlating the color profiles with environmental variables like humidity, moisture, and soil quality, orange farmers can develop a better picture of which conditions make the best oranges. They can then apply these findings to their agricultural practices to improve their crops.

juicing oranges
Spectrophotometric color measurement allows you to analyze the color of your oranges with the highest degree of accuracy possible. Image Credit: Unsplash user Keilidh Ewan

Spectrophotometers Assess How Orange Oranges Are

So what is the most desirable color of a juicing orange? The fine folks at the United States Department of Agriculture (USDA) has furnished an answer. In 1983, the USDA combined all previous references into a color scale for orange juice with six gradations, the first grade being the most desirable.3  Orange juicers can compare their products against this scale to see how well they rank. It is possible to order a set of six graduated cylinders from the USDA, each one corresponding to one of the grades. Orange juicers can then visually compare their products against the color of the liquids in these cylinders. Of course, there’s also a much simpler, more accurate method: spectrophotometric analysis.

Using a spectrophotometer eliminates the necessity of ordering the USDA’s graduated cylinders. Instead, color standards for orange juice can come pre-programmed in the instrument, allowing for greater specificity than is possible via visual inspection and ensuring the highest degree of grading accuracy. In fact, HunterLab spectrophotometers were used by the USDA to develop and define their color standards in the first place.4  

Spectrophotometers can fill multiple niches within an orange grove’s operations. They have immediate applications on the juicing floor, helping ensure juice products meet color quality standards for their grades. However, these instruments can also be useful in improving a grove’s agricultural output. Spectrophotometers can be used both by farmers and agricultural corporations to analyze the groves on their land as well as by agricultural researchers to study the factors that influence the color of oranges on a worldwide scale. Armed with this knowledge, orange grove operations can adjust their growing practices as necessary to produce a superior yield.

The HunterLab Difference

At HunterLab, we’ve been working with the orange industry for decades to develop the highest quality color measurement instruments. Our technologies and expertise have made us a trusted name in orange agriculture, and we’re proud to continue in this tradition. We have a complete range of spectrophotometers engineered to analyze juice color, and our ColorFlex EZ Citrus spectrophotometer was designed specifically to measure the color of orange juice concentrate. Contact us to learn more about how the ColorFlex EZ Citrus or our other instruments can improve your orange operation.

  1. “More Than Meets the Tongue: Color of a Drink Can Fool the Taste Buds Into Thinking It Is Sweeter,” February 16, 2007, https://www.sciencedaily.com/releases/2007/02/070212182136.htm
  2. “Carotenoid Chameleons: Scientists Chart How Orange Juice Changes Color”, March 18, 2015, https://www.beveragedaily.com/Article/2015/03/18/Carotenoid-chameleons-Scientists-chart-how-orange-juice-changes-color#
  3. “United States Standards for Grades of Orange Juice”, 1983 https://www.ams.usda.gov/sites/default/files/media/Canned_Orange_Juice_Standard%5B1%5D.pdf
  4. “Equivalent Color Scores for Florida Frozen Concentrated Orange Juice,” 1969, http://fshs.org/proceedings-o/1969-vol-82/200-205%20(HUGGART).pdf
Transmission Spectrophotometers Ensure Color Quality in Liquid Dish Soap
liquid dish soap
Dish soap color has little to no effect on its cleaning power but can have a big impact on consumer perception. Image Source: Pexels user Burst

Why does liquid dish soap have a color? After all, the essential ingredients of liquid dish soap are water, cleaning and foaming agents, antibacterials, stabilizers, and agents that control thickness and clarity.1 None of these are naturally colored candle apple green, blue raspberry, or lemon, nor do any of their mixtures result in these bright, final colors. To achieve these colors, manufacturers must mix in dyes during the blending process. So why go to the extra trouble, spending extra time and money procuring, assessing, and admixing dyes? For the same reason that perfumes are included: customer perception.

liquid dish soap
Many customers will seek out a liquid dish soap by color. Image Source: Pexels user Pixabay

Color Impacts Consumer Perception

Dyes have no effect on the cleanliness of the dishes. Yellow dish soap works precisely as well as blue, green, or orange dish soap. Yet, customers will prefer one color of soap to another and will purchase their chosen color preferentially when the time comes to replenish their supply. Most customers intuitively understand that yellow soap does not clean better than blue soap; their preference is not, then, based on assumptions of relative efficacy. Rather, it is the color itself that they like. Perhaps it is the color of soap they grew up with, perhaps it matches the color scheme in the kitchen, perhaps it corresponds to the scent they like, perhaps it is their favorite of all colors. Whatever the reason, dish soap color can be a significant factor in purchasing decisions.

Not only do customers choose dish soap partially in response to an emotional reaction to color, color can also inspire loyalty in a brand. Rather than making a new choice each time customers return to the store to resupply, we shop to a significant degree based on habit. If “the blue one” worked well last time, they’re likely to choose “the blue one” again. In this way, customers begin to recognize and associate brand with color and color becomes an important aspect of a brand’s identity. Even if competing liquid dish soap manufacturers have a similar color complement, small differences in shade and hue can be enough to distinguish the products. These differences work best in combination with bottle shape and size and label text and images to create a cohesive aesthetic and promote both brand recognition and loyalty. The importance of color in liquid dish soap requires manufacturers to implement a strict regimen of color quality control.

liquid dish soap
Spectrophotometers are vital to ensure accurate and consistent dish soap color. Image Source: Unsplash user Markus Spiske

Spectrophotometers Ensure Brand Consistency

The ideal method of liquid dish soap color quality control relies on spectrophotometric color measurement. Transmission spectrophotometers measure the exact color of translucent or transparent liquid objects, perfect for translucent liquid dish soap. Reflectance spectrophotometers measure the color of opaque liquids or solids and would be necessary for companies manufacturing opaque liquid dish soap. Certain advanced spectrophotometers, such as the UltraScan Pro from HunterLab, are capable of measuring both transmittance and reflectance color.

Whether measuring translucent or opaque liquid soaps, spectrophotometers are an essential quality control tool.Unlike human observers, who see color subjectively, spectrophotometers measure color on an objective, numerical basis. This means that spectrophotometers will always measure color to your exact standards. While the observations of human color testers may vary due to biological and environmental factors, those of spectrophotometers will remain precise over tens of thousands of measurements.

Not only can spectrophotometers be useful during the mixing process to ensure that each batch of dish soap is the proper color before moving to the next stage of production, they can also be helpful in the realm of market research and color development. By spectrophotometrically recording the exact shades that customers prefer in focus groups and other studies of color preference, these instruments allow manufacturers to easily replicate the shade that customers respond to best. These recordings can be used as future standards as manufacturers continually search for the perfect dish soap color.

The HunterLab Difference

At HunterLab, we’ve been developing color measurement solutions for over six decades. Our reputation for quality has led top companies to choose HunterLab to perfect their product development and manufacturing processes. Because we work closely with our customers to understand their unique needs, we’re able to offer instruments ideally suited for liquid dish soap quality control. Contact us to learn more about our products and lets us help you find the perfect tools for your needs.

  1. “Palmolive Ingredients,” 2017 http://www.palmolive.com/ingredients
Keeping the Golden Gate Bridge Golden: How Paint Suppliers for Bridges Keep Colors Consistent
bridges color
It takes a lot of paint to keep the Golden Gate orange. Image Credit: Unsplash User Andreas Selter

It’s a bit of an exaggeration to say that the Golden Gate Bridge is painted from end to end each year. In fact, the only time it was ever painted end to end is the first time it was ever painted, nearly a century ago. Since then, there has been touch-ups and maintenance painting, as well as a 30-yr project to remove and replace lead-based paint that ran from 1965 to 1995.1. However, even these regular touch-ups require a full-time painting staff and, of course, tons of paint. The story is the same for most of the bridges in the United States. Initially and on an ongoing basis, enormous volumes of paint are required to prevent corrosion and to keep the bridge looking trim, rain or shine.

The Golden Gate Bridge is notable for its span, but also its color. The particular shade of orange used is immediately recognizable and only one large suspension bridge in the world boasts a similar color: the 25 de Abril bridge connecting Lisbon, Portugal to Almada. While few other bridges are painted similarly to the Golden Gate Bridge, most other bridges are painted with the same attention to detail. That is to say, that each bridge is its own color as distinctly as the Golden Gate is orange. Naturally, this presents an opportunity for paint makers. The supplier who mixes orange for the Golden Gate Bridge enjoys a steady revenue stream from the ongoing maintenance. Paint manufacturers able to consistently produce paint that meets the color specifications of bridges stand to benefit from a constant flow of revenue.

bridges color
Bridges across the country require constant repainting. Image credit: Unsplash User Jeffrey Blum

Spectrophotometers Ensure Paint Color Consistency

The best way to ensure paint color consistency is to employ spectrophotometers as part of the quality assurance process. These instruments are the most accurate and effective way to measure color as part of an industrial application, like paint production. Small enough to fit on a benchtop and fast enough to measure multiple samples per minute, reflectance spectrophotometers assess the color of opaque liquids and solids by measuring reflected light. This makes them an ideal instrument for rapidly determining whether paint batches meet color specifications.

Spectrophotometers are a significant improvement over other color quality assurance options, especially human observers. When it comes to distinguishing between slight differences in shade on a consistent basis over the course of years, the human eye and human brain cannot match the objective quality of the spectrophotometer. Depending on the observer, the time of day, the person’s mood, the ambient quality of light in the room, and the state of the comparison sample, human observers may make color identification errors. Needless to say, these errors can be costly, as paint is wasted and rework is made necessary.

bridges color
The bright blue paint requires consistent maintenance to keep up. Image Credit: Unsplash User Robert Conklin

Spectrophotometers Provide Objective Data

With spectrophotometers, the potential for color inconsistency inherent to visual inspection is eliminated. Using controlled bursts of light and computer precision, spectrophotometers can identify shades with minute specificity. Their judgment is unaffected by mood or time of day and is based on objectively determined programmed standards. Further, spectrophotometers identify color numerically. This allows them to communicate color objectively and consistently; the precise orange hue of the Golden Gate Bridge is rendered as a series of static, numerical values, rather than “Golden Gate Orange.” This ensures greater consistency in standards and that, as a manufacturer, you’re always able to produce the exact shade your client requests.

Spectrophotometers are versatile instruments as well. Few paint manufacturers produce paint in a single color for a single client. Rather, a paint manufacturer may be producing dozens or hundreds of colors of paint, for dozens or hundreds of applications, from bridges and other large infrastructure to retail wall paint. Fortunately, spectrophotometers are able to save color standards in their memory for technicians to recall as needed. So no matter how many different shades of orange a manufacturer produces, the spectrophotometer will be able to instantly determine if each batch of paint is the correct color based on its archive of color standards.

The HunterLab Difference

HunterLab spectrophotometers have been used for decades to assess paint color for projects big and small. Our instruments offer the highest level of accuracy and precision available on the market, making us one of the most trusted names in color measurement technologies today. Combined with our customizable software packages, HunterLab spectrophotometers gives you unprecedented color quality control combined with versatile, user-friendly designs. Contact us today to find the right color measurement solution for your needs

  1. “Frequently Asked Questions About the Golden Gate Bridge”, 2017, http://goldengatebridge.org/research/facts.php#PaintEndtoEnd
Spectrophotometry Makes Color Consistency in Towel Production Possible
color consistency
A teal towel swaddles a newborn infant. Image Credit: Unsplash user Sean Roy

There isn’t a household in America that doesn’t have a towel. Most have several. It’s a ubiquitous item; across the world people get wet and need to get dry. The practical and psychological importance of the towel is immortalized in this passage from Douglas Adams’ The Hitchhiker’s Guide to the Galaxy:

A towel, it says, is about the most massively useful thing an interstellar hitchhiker can have. Partly it has great practical value. You can wrap it around you for warmth as you bound across the cold moons of Jaglan Beta; you can lie on it on the brilliant marble-sanded beaches of Santraginus V, inhaling the heady sea vapours; you can sleep under it beneath the stars which shine so redly on the desert world of Kakrafoon; use it to sail a miniraft down the slow heavy River Moth; wet it for use in hand-to-hand-combat; wrap it round your head to ward off noxious fumes or avoid the gaze of the Ravenous Bugblatter Beast of Traal (such a mind-bogglingly stupid animal, it assumes that if you can’t see it, it can’t see you — daft as a brush, but very very ravenous); you can wave your towel in emergencies as a distress signal, and of course dry yourself off with it if it still seems to be clean enough.

More importantly, a towel has immense psychological value. For some reason, if a strag (strag: non-hitch hiker) discovers that a hitchhiker has his towel with him, he will automatically assume that he is also in possession of a toothbrush, face flannel, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet weather gear, space suit etc., etc. Furthermore, the strag will then happily lend the hitchhiker any of these or a dozen other items that the hitch hiker might accidentally have “lost.” What the strag will think is that any man who can hitch the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still knows where his towel is, is clearly a man to be reckoned with.

— Douglas Adams, The Hitchhiker’s Guide to the Galaxy 1

For towel manufacturers, the importance of towels in everyday life is overwhelmingly good news. Towels are big business. Demand for towels is consistent; as a staple item, towels are purchased at a relatively stable rate. The downside, if it can be called that, is that to compete, towel manufacturers must produce enormous amounts of towels for very large customers. Whether their towels are sold via big-box retail stores such as Target or Walmart, online via Amazon or through national and regional distributors to smaller stores, towel manufacturers must be able to produce huge amounts of identical towels. As such, strict quality control measures are essential throughout the manufacturing process. When it comes to color, spectrophotometers play a central part in ensuring consistency.

color consistency
Towels come in many colors and designs. Image Credit: Unsplash user Mike Meroz

Color Quality Assurance Processes Reduce Off-Goods

Customers expect consistency, whether they are buying two towels or 200. Towels that don’t meet specifications cannot be sold at regular price and must be disposed of or sold at a reduced price as off-goods, which can result in significant economic losses. Further, a high percentage of off-goods can compromise customer satisfaction as well as brand reputation. If shipments are delayed due to the need to make up work or if clients receive shipments which do not meet specifications, they may consider seeking another manufacturer. After all, with such a large market for towels, there are many, many towel manufacturers, each one ready and willing to take business from their competitors.

One of the simplest ways to lose a batch of towels to off goods is to fail to meet color specifications. Whether a towel is printed or dyed, each towel made to a certain design must fall within the design’s established color tolerances. If a batch should fail to do so, it must be sold at the reduced off-goods price. If the batch should make it all the way to the client before being rejected for color, extra costs will be incurred. For this reason, towel manufacturers make color quality control a principal part of their quality assurance processes.

Many factors during the dyeing or printing process can cause accidental off-coloration. If color standards are communicated improperly, a manufacturer will end up producing towels to the wrong specification. The physical attributes of the towel cloth can make a difference as well, as linen, cotton, terry, synthetics, and other towel cloths all react to dyes in unique ways and print with differing degrees of color fastness. Natural and synthetic dyes, as well as different color dyes, have differing degrees of fastness as well. The formula for producing a teal towel on terry cloth will be different than on linen. This is complicated by blended fabrics and the dye mixes needed to produce unique colors. Furthermore, simple mistakes during the dyeing process, such as poor temperature control, water impurity, clogs or residue in the supply lines, or residue in the mixing vat, can all lead to discoloration as well. Finally, if the process is automated, simple computer errors can cause improper coloration. To prevent color irregularity, manufacturers must regularly and consistently test the color of their towels.

color consistency
Towels are a regular part of everyday life. Image Credit: Unsplash user Dan Gold

Spectrophotometers Prevent Waste

The ideal instrument for testing the color of towels rapidly and accurately is the reflectance spectrophotometer. These instruments assess the color of objects by bouncing controlled bursts of light off samples and analyzing the reflections. A sample can be measured in five seconds or less with unerring accuracy. By testing towel samples from test batches, manufacturers can determine whether a full production run will produce towels of the proper color. Samples can also be tested during the full run to be sure that the towels are consistently coming out the right color. Finally, samples can be tested after the towels are dried, cut, and packaged to be shipped to be sure that every batch sent to the client is within color tolerance standards.

While the use of spectrophotometers is easy to learn, any tool is only as good as its user. The flexible, porous nature of towel textiles can create measurement difficulties if not properly controlled for. To ensure proper measurement, a backing should be placed in the compartment behind each towel sample. This is to reflect any light that passes through the towel itself. Naturally, the backing should be the same color and material for each usage. Also, towels, like most textiles, are flexible by nature. As such, samples should be secured to ensure they don’t bend or pillow into the observation port. Proper technique informs proper measurement.

Another benefit of spectrophotometers is that they improve color communication. No matter how flawless a manufacturer’s color quality assurance is, if the desired color hasn’t been communicated correctly, they risk producing the wrong color towels. Spectrophotometers allow for exact communication thanks to their numerical identification of color. Human descriptions of color, such as “blue,” “mauve,” or “sunset orange” are fuzzy and imprecise. By contrast, spectrophotometers communicate color in tri-variable numerical sets, identifying each shade with decimal accuracy. This clarifies all communications both internally and externally and ensures color standards stay exactly the same across time.

The HunterLab Difference

With 65 years of color measurement expertise, HunterLab is the leading name in industrial spectrophotometry. Our instruments are used in textile production facilities across the nation and the world owing to their reputation for accuracy, ease of use, and versatility. Contact us today to learn which spectrophotometer would be ideal for your towel production facility.

  1. “Towel Day,” May 2017, https://en.wikipedia.org/wiki/Towel_Day
Spectrophotometry Ensures Total Transparency in Smartphone Crystal Glue
smartphone crystal glue
Smartphones have created their own industry ecosystem. Image Credit: Unsplash user Gilles Lambert

Revolutionary products create their own ecosystems. Take the automobile for example. Cars have changed the face of the world. Their usage created a need for paved roads, highways, driveways, and parking lots. As a result of their ubiquity, communities changed their layouts to make car ownership and transportation easier. It doesn’t stop there, though—the ecosystem the automobile created has large niches for secondary industries dependent on the car. Automotive repair shops, for instance, wouldn’t exist with automobiles. Neither would dealerships or, perhaps most profoundly, the innumerable factories that create automotive parts to be assembled by car manufacturers. After all, it takes about 30,000 parts 1 to build a car, and every one of those parts needs to come from somewhere, as does all the glue to hold it together. Of course, all the raw or processed materials needed to make all those automotive parts need to come from somewhere as well. Without the car, vast industries wouldn’t exist. Oh, did I mention that cars require gasoline and oil to run?

Of course, cars are old news at this point. If they don’t fly, it’s hard to get excited. What is new, and what is cool, is the smartphone. Like the automobile, the smartphone has changed the world, creating infrastructure and restructuring communities. Also like the automobile, the smartphone has created a huge ecosystem for secondary industries to thrive in. It doesn’t take 30,000 parts to make a smartphone, but the industry still requires huge amounts of precisely engineered components. For glue manufacturers, smartphones present a huge opportunity.

smartphone crystal glue
Smartphone glue must be absolutely clear to keep the display clean. Image Credit: Unsplash user Jordan McQueen

Meeting the Stringent Requirements of Smartphone Companies

Naturally, given the exacting requirements of smartphone manufacturing, only the top companies— those that are able to meet stringent manufacturer specifications on time and on budget—are able to secure supply contracts with Apple, Samsung, and other smartphone manufacturers. Supply companies competing not only with each other but also with manufacturers of smartphones themselves, including Foxconn and other high-end manufacturers. But with these challenges comes the potential for great reward. To land a contract supplying a smartphone manufacturer is lucrative, to say the least. As a result, glue manufacturers are vying for the opportunity to play the big new game of the century.

The glue that holds smartphone display screens to their frames must fulfill several requirements. It must be strong, controllable, durable, and water-resistant. On top of all that, it must be absolutely colorless and transparent. Smartphone displays are meant to be visible, after all. Any color or haze whatsoever in the glue would ruin the effect. As such, glue manufacturers supplying smartphone makers must implement strict and effective quality assurance processes to make sure their glue stays clean. The stakes are high—if a company ships too many batches of glue that doesn’t meet the standards, they stand a chance of losing their contract to a competitor.

smartphone crystal glue
The ubiquity of smartphones means lucrative contracts for their parts suppliers. Image Credit: Unsplash user Samuel Zeller

Spectrophotometers Determine Glue Quality

The margin for error in the manufacture of smartphone glue is razor thin. For this reason, it’s essential to turn to instrumental color and haze quality control over human observation. Human observers simply do not have the visual acuity and specificity to reliably detect the small deviations from transparency that pass or fail a batch of glue. Without instrumental analysis, it is unlikely that any glue manufacturer will be able to produce glue to meet the requirements of smartphone manufacturers.

The best way to ensure that smartphone glue stays colorless and free of haze is to test each batch with a transmission spectrophotometer and haze measurement instrument. Transmission spectrophotometers detect the color—or absence of color—of transparent liquids and solids by measuring a burst of light sent through that object. They can determine whether a sample of glue meets transparency standards within a matter of seconds. Haze measurement instruments operate in a similar way, using a controlled burst of light to detect the presence of any haze or contamination in transparent substances. While these processes have traditionally required the use of separate instruments or multiple measurements, HunterLab’s Vista is capable of capturing both haze and color data in a single measurement, significantly improving efficiency.

The HunterLab Difference

With over six decades of experience in color quality control, HunterLab has a long track record of successful color measurement applications. Our products are found in the laboratories of the top chemical companies in the world and are used to guarantee that the chemical products manufacturers rely on are always up to grade. Having worked closely with high-end chemical manufacturers, we’ve been able to design our instruments to meet the specific needs of the industry. Contact us today to find the spectrophotometer that ideal for your operation.

  1. “How Many Parts is Each Car Made Of?”, 2017, http://www.toyota.co.jp/en/kids/faq/d/01/04/
Spectrophotometers Ensure Color Quality in Acrylic Molding
color quality acrylic
Acrylic plastics are used in a wide variety of consumer products, and are produced in many different colors. Image Credit: Unsplash user Sebastian Pichtler

Cheap. Durable. Versatile. These are the qualities that have led to the rise of the acrylics over the past century. Attractive across a broad range of industries, acrylics are now produced on a constant basis in vast quantities. They are found everywhere from airline windshields to hot tubs to jewelry, and their popularity shows little signs of diminishing. The caveat, however, is that such high demand has created strong competition in the industry. Acrylic manufacturers who are unable to meet industry standards for price, efficiency, and quality control may find themselves losing market share to competing firms.

One of the easiest ways to produce a substandard and unsaleable batch is to create incorrect or inconsistently colored acrylic. Customers may have very specific demands for the coloration of their products and rely on manufacturers to produce acrylics which meet their standards. As acrylic in its basic form is transparent, each shade requires the inclusion of discrete mixes of color additives. Given that the production of acrylic plastic requires highly specific temperatures, timing, and amounts of pigment, each shade requires its own unique formula. With such specificity demanded, it’s all too easy for a slight mistake to push a batch beyond the bounds of tolerance.

color quality acrylic
Monitoring the color of acrylic products is essential to meeting customer expectations. Image Source: Flickr user tiffany terry

Spectrophotometers Are Essential For Acrylic Color Quality Control

Acrylic manufacturers must implement a rigorous color quality assurance system to complement their various other methods of quality control. Fundamental to successful acrylic color quality control is the spectrophotometer. These instruments can detect the color of transparent or opaque materials with unerring and infinitesimal precision.

Put into practice, spectrophotometers aid acrylic manufacturers in two main ways. First, acrylic manufacturers can assess test batches to ensure that they result incorrectly colored plastics before they are scaled up for a full run. This allows manufacturers to fine tune their formulae, making certain that when the time comes to commit the materials and energy needed to produce a full product run, the end result will be exactly the right color.

Next, spectrophotometers can be used to assess the color of acrylics both during and after the manufacturing process. This ensures that the desired color is maintained throughout the production phase and that each batch of acrylic produced falls within established color tolerance standards before it is shipped to the client. Keeping a close eye on color during manufacturing helps make sure that no variations occur. Should any variation be detected, manufacturers are able to correct it with a minimal loss of time, energy, or material. By subjecting each batch to a final scan before shipping it to a client, manufacturers can protect themselves from the rework and possible reputational damage that can result from delivering a substandard batch.

color quality acrylic
Acrylics manufacturers must often make very large batches of consistently colored plastics. Image Credit: Unsplash user Peter Feghali

Spectrophotometers Set Color Standards Across the Industry

The use of spectrophotometers also helps manufacturers communicate specific color requests with their clients. As opposed to the fuzzy language of ordinary color communication, spectrophotometers render color on a numerical scale. The hitch standardization process ensures that each instrument using the standard system interprets color the same way and allows operators to adhere to color standards with decimal accuracy, even if working thousands of miles apart. Further, it ensures that when manufacturers test their batches for quality control, they are testing them against the exact standard that their clients will be judging them against.

Designed for industrial use, spectrophotometers are rapid, reliable, and small enough to easily fit in standard industrial laboratories and production floors. They can be configured to measure samples of various sizes and can make each measurement in under five seconds. An additional benefit is that technicians can operate spectrophotometers without extensive training. To determine if a batch meets the standard, all they would need to do is select the standard from the instrument’s memory, insert the sample, press a button on the screen, and read the results. The instrument itself will display whether a sample has passed or failed, so technicians do not need to spend extra time interpreting the readout.

The HunterLab Difference

At HunterLab, we’ve been designing spectrophotometers for industrial use for over sixty years. Our instruments are used by acrylic manufacturers across the world and set the standard for industrial color measurement. Their reliability, efficiency, and durability make them ideal choices for any industrial laboratory or production floor. Contact us today to find the right spectrophotometer for your manufacturing process.

Spectrophotometry Enhances Color Consistency in Architectural Glass
architectural glass
Reflective glass has replaced concrete in the facade of many modern buildings. Image Credit: Flickr User paul bica

“Why didn’t anybody check that?” asked Stephanie. “You must’ve noticed it during installation, right? It must’ve been pretty obvious that a quarter of the panes weren’t the same color as the rest. How come you didn’t stop and double check with me?”

Around the room, the heads of her contractors nodded in guilty agreement. A few hid behind their coffee cups. Stephanie shook her head. “We did notice,” spoke up Ted, her general. “But we were already behind and we figured you knew about it. You weren’t around to check with. Sorry, Stephanie. I should’ve called you.” “Yeah,” said Stephanie. “You should’ve. We’re going to get another week behind taking them down and reinstalling. Alright, let’s go. You know what to do.”

As they filed out of the trailer, Stephanie stopped on the bottom step and looked up at the building. In the facade of steel-blue glass building, copper-colored panels stood out like missing teeth. She shook her head again and picked up the phone. It was time to have some words with the manufacturer.

Glass Color Consistency Is Essential for Brand Reputation

For manufacturers of architectural glass, color is a major component of brand. Architects and contractors purchasing glass products for buildings expect that glass will conform to their exacting standards. If manufacturers deliver off-color sheets, not only will they be required to provide a replacement at their own cost, they may suffer significant reputational damage as well. Architects often share advice on their materials sources within their firms,  networks, and professional associations. As a result, a manufacturer incapable of consistently producing glass within established color tolerance standards stands not only to lose future projects from a single customer but referral projects as well.

architectural glass
Architectural glass must be consistently colored over large areas. Image Credit: Flickr user Bernard Spragg. NZ

Spectrophotometers Ensure Consistent Coloration

Given the need for color consistency, manufacturers must employ rigorous color quality control processes. However, architectural glass presents unique color measurement challenges. Architectural glass is either transparent, reflective, or a combination of both.1  Most modern buildings use glass that is reflective when viewed from the building’s exterior, and transparent when viewed from the interior.
Only by testing their products with spectrophotometers before they leave the works can manufacturers be assured they are the proper color. Although reflective and transparent objects require different methods of color measurement, spectrophotometers can be built to measure either. Certain models can combine both functions into a single instrument.

Further, spectrophotometers measure color objectively and are not subject to the inaccuracies inherent to human observation. Measurement is rapid and results can be viewed immediately and saved to a company’s archive for documentation or research purposes. Not only are these instruments capable of making the necessary measurements; they do so accurately, quickly, and repeatedly.

architectural glass
Many, if not most, urban high-rises now call for large amounts of glass paneling. Image Credit: Flickr User paul bica

Numerical Communication of Color Prevents Ambiguity

One of the greatest advantages of spectrophotometry is that it eliminates uncertainty and ambiguity in the communication of color standards. Using custom-developed color measurement software, the instruments assign color numerical values on a tri-variable scale. This allows precise communication, down to decimal accuracy, of color tolerances. Using this scale prevents mix-ups related to improperly communicated standards, and any disagreements these mix-ups may cause.

Having numerical color standards also allow manufacturers to ensure color consistency across multiple manufacturing locations, an essential component of quality control in an increasingly globalized marketplace. These standards allow them to communicate across time as well. If an architect should order “the same color as last time,” for a new building, all the manufacturer has to do to find that exact color is search through their archived order data. It can aid manufacturers in sourcing related materials from their suppliers as well, such as dyes, paints, and laminates.

HunterLab Innovation

HunterLab has more than six decades experience developing color quality solutions for the industrial glass industry. Our instruments are used by many leading glassmakers to measure a variety of laminated, painted, tinted, and other glass products. As we’ve worked with these customers, we’ve listened to them as well. Each new instrument we’ve designed has been informed by feedback from our clients. We’re constantly improving our products so that you can keep improving yours. Contact us to learn more about which spectrophotometric instruments are best suited for your quality control processes.

  1. “73rd Conference on Glass Problems,” April 22, 2013, https://books.google.ca/books?id=zNs90eyR84EC&dq
Spectrophotometers Enhance Felt Color Quality Control
felt color
Makers of felt hats depend on manufacturers for consistent coloration. Image Credit: Unsplash user Onur Bahçıvancılar

Felt is a highly diverse fabric, used in applications from clothing to children’s toys to automotive and interior design and many more. Just ask Lucy Sparrow. The artist recently opened 8 ‘Til Late, a bodega near Manhattan’s High Line stocked from floor to ceiling with replica products made entirely of felt, from peanut butter to pickles, burritos to breakfast cereals. So what attracted Sparrow to felt? “Pure practicality,” she says. “It doesn’t fray, and also it’s available in more colors than you can possibly imagine. The color-matching capabilities are absolutely awesome. I like that the whole art practice comes down to one material.” 1

Indeed, color is perhaps the most attractive quality felt, regardless of who is using it. Whether felt is to be part of a greater design or used on its own, felt manufacturers must ensure their products are consistently colored.

felt color
Vividly colored felt can even be used by creative bakers to make cupcakes. Image Credit: Flickr user Melanie Hughes

Felt Manufacturers Require Color Control

Felt products must be color consistent both for general production and for customer orders. In general production, standard cuts and colors of felt are produced in bulk and purchased by designers as is. Designers and other shoppers who buy general production felt often are seeking to replicate patterns over a large amount of product and need their felt to always be the same color to fit their pattern. If the felt products they have to choose from vary over time or over a single sheet, they may choose to seek felt from a more dependable source.

For custom felt production, where designers order specific cuts and colors from felt manufacturers, color quality control is even more essential. When designers place their orders, they have a clear idea of what color their felt needs to be. They’re paying more for a custom order over generally produced felt for the purpose of ensuring that their felt product will be exactly the color they desire. For these customers, who often represent large orders and have continuing business relationships, manufacturers must be able to produce the proper felt color without deviation or error.

Numerical Color Definition Is Essential for Communication

In either bulk or custom applications, the process of color quality control begins with communication. Specific shades of colors are difficult to communicate because the human language lacks clearly defined words for the myriad potential shades. So, when dyeing felt to meet the same bulk standard or a customer’s specific request, simply dyeing it “maroon” or “cerulean” isn’t enough to guarantee that it will be the same color as last time, or the color the customer desire. For this reason, manufacturers must define colors using CIE L*a*b*, the numerical scale used by spectrophotometers. By assigning colors specific numerical values, manufacturers can replicate any color with decimal precision. Both standard production colors and customer orders can be rendered numerically, ensuring that dyeing process is always working towards the correct end goal.

felt color
Manufacturers rely on spectrophotometers to produce felt products that meet fashion designer’s standards. Image Credit: Flickr user Cecilia Coelho

Dyemasters Depend on Spectrophotometers

Knowing the precise color of felt to be produced is only a part of the battle. It still remains to dye the felt to standard and then to assess that the end result is the proper color. The dyeing process can be difficult and inexact, due to variations in raw materials and the colorfastness of different pigments on felt. To control the end result, cleanliness of all the dyeing tools must be maintained to prevent contamination. As issues will arise with raw materials and each different set of pigments, employing a dyemaster who can compensate for these issues in situ is necessary. But even the best dyemaster is only as effective as the tools they’re working with. Any good dyemaster will depend on their spectrophotometer.

Spectrophotometers are color measurement instruments. Reflectance spectrophotometers are used to assess the color of felt and other opaque products. These instruments measure color by reflecting bursts of controlled light off felt and other objects and analyzing the light that returns. Spectrophotometers are capable of determining precise shades, and returning their results as either a simple pass/fail function or as a clearly defined numerical set. Only with a quality spectrophotometer can dyemasters ensure that their felt matches the exact standards of a customer’s order or the established standard for bulk production. Ideal for laboratory conditions, spectrophotometers take up little bench space, measure rapidly, and are easy for technicians to master. With a spectrophotometer in their laboratory, manufacturers can ensure their felt is always the exact color it needs to be before it ever leaves the factory.

The HunterLab Difference

With six decades of experience designing color measurement solutions for the textile industry, HunterLab has come to understand what dyemasters and fabric manufacturers seek in their quality control processes. HunterLab spectrophotometers measure accurately and rapidly and have long provided dependable measurement with cutting-edge controls and software. Contact us today to learn which spectrophotometer can best improve your quality control process.

  1. “Lucy Sparrow’s Felt Bodega Hits The Standard, High Line”, 5/25/17,   http://www.standardhotels.com/culture/lucy-sparrow-artist-felt-8-till-late-bodega-cornershop
Transmission Spectrophotometers Clarify Color Consistency in Polyurethane Coatings
polyurethane coatings
Boatbuilders use polyurethane to protect and extend the life of their boats. Image Credit: Unsplash user Jon Flobrant

It takes a lot of work to refinish an old wooden boat and restore it to its former glory. Any holes must be patched and rotten wood replaced. The entire body of the boat must be sanded down, inch by inch, and the boards must be caulked to make it watertight. It is time-consuming, exacting labor, the results of which must be preserved using a protective substance designed to keep the wood from rotting all over again. This is where polyurethane comes in.

Polyurethane is widely used in woodworking for its protective properties. Considered essential by homeowners, craftsman, furniture makers, and contractors, polyurethane forms a protective, waterproof coating for wooden surfaces, enhancing the durability and lengthening the life of all forms of wooden objects. Typically, polyurethane is intended to be entirely clear to preserve the color of the natural wood or chosen stain. However, some oil-based polyurethanes can add a slight hue to the color of the wood they protect.1

Those who work with polyurethane depend on manufacturers for color consistency, whether they are protecting a carefully chosen stain or preserving the beauty of natural, unstained wood. As such, polyurethane must be transparent or deliver a predictable hue to allow woodworkers to realize their vision. Manufacturers who produce consistent, high-quality polyurethanes are much more appealing to customers than those who do not, as woodworkers know they can depend on these polyurethanes to bring out the best in their products both functionally and aesthetically. In order to develop and capitalize on the advantage provided by consistently colored coatings, manufacturers must employ end-to-end color quality assurance processes using modern spectrophotometric instruments.

polyurethane coatings
Polyurethane coatings protect richly colored wood. Image Credit: Unsplash user Ryan Riggins

Color Quality Assurance Is Essential for Polyurethane Coatings

The primary advantage of polyurethanes over other polymer products is that polyurethanes are made and sold in their final form in the laboratory or factory and do not require any intermediate steps after manufacture before being used.2 Polymers such as polyethylene or polypropylene, on the other hand, are first produced and sold in an intermediate form, such as films, powders, and granules. To create a final product, they must be processed a second time. Due to the efficiency of the polyurethane process, color quality assurance processes are relatively simple for manufacturers to implement.

First, manufacturers must test the color of their raw materials. The basic building blocks of polyurethane coatings are alcohols with two or more hydroxyl groups per molecule, which combine in an exothermic reaction to produce polyurethane. These alcohols, typically toluene and methylene, must be assessed before the reaction to determine their purity and the color they will eventually impart to the polyurethane. Ideally, these alcohols will be “water white,” or entirely transparent, prior to use. This can be determined using the APHA/Pt-Co/Hazen scale.

After the reaction is complete, manufacturers must test the finished polyurethane to ensure it is colorless or a predetermined hue. Impurities or an inexact production process can result in off-color polyurethane that will compromise the finished appearance of customers’ products. To be certain that each batch of polyurethane is the correct color before it is shipped to distributors or customers, manufacturers must diligently measure samples. The detection of unwanted coloration in finished polyurethane not only prevents customer dissatisfaction, it can also point to issues in the production process that require correction.

polyurethane coatings
Clear polyurethane coatings protect wood while preserving its color. Image Credit: Unsplash user Hudson Hintze

Measuring Color and Haze with Transmission Spectrophotometers

To accurately measure transparent liquids, manufacturers employ transmission spectrophotometers. These instruments measure the color of transparent and translucent materials by passing a controlled beam of light through a sample, then collecting and analyzing the light on the other side. In doing so, they are able to rapidly detect and quantify the exact color of the sample. These instruments are ideal for analyzing polyurethanes and their alcohol precursors, allowing you to determine how close your sample is to being water white.

Certain transmission spectrophotometers, such as HunterLab’s Vista, can also measure haze in liquids. This is an essential step for determining transparency and detecting contaminants in toluene, methylene, or polyurethanes both before or after the production process to ensure that your product performs as customers expect. Unlike other spectrophotometers, the Vista can measure color and haze simultaneously, eliminating the need for multiple measurements or instruments, minimizing sample preparation time, and optimizing efficiency. The Vista comes paired with our Essentials color management software, which is preloaded with a comprehensive range of color scales and indeces, including the APHA/Pt-Co/Hazen scale, making it easy to correctly classify and share color information.

HunterLab Quality

With over sixty years of experience working with the chemical industry, we at HunterLab design our color measurement instruments to address the needs of chemical manufacturers. Our range of spectrophotometers, accessories, and customizable software options offer innovative solutions to the challenges faced by this growing industry. No matter how sensitive the chemical or delicate your process, our instruments are ideally suited to your color and haze measurement needs. Contact us to learn more about how the Vista and or any of our renowned spectrophotometers can improve your color quality assurance processes.

  1. “What’s the Difference Between Polyurethane,  Varnish, Shellac, and Lacquer?”, 2013, http://www.diynetwork.com/how-to/skills-and-know-how/painting/whats-the-difference-between-polyurethane-varnish-shellac-and-lacquer
  2. “Polyurethanes”, 2016, http://www.essentialchemicalindustry.org/polymers/polyurethane.html
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