As leading apparel and footwear brands know, color is a key factor in every purchase decision. But ask anyone in material sourcing or manufacturing, and they will tell you that achieving accurate, consistent color in production can be a challenge – especially when assembled products include multiple materials such as cotton, leather, plastics, synthetics and more.
Achieving the best color across a complex textile supply chain requires a range of color management solutions, including a spectrophotometer. To choose the right spectrophotometer, you must understand how these color measurement devices work and when to use them in your workflow. It’s an important choice that can streamline color specification, formulation, dyeing, and quality assurance processes, and reward you with less waste and faster production times.
What Is a Spectrophotometer?
Spectrophotometers are color measurement instruments. As part of a color control program, brand owners and designers use them to specify and communicate color, and manufacturers use them to monitor color accuracy throughout production. Spectrophotometers can measure just about anything, including liquids, plastics, paper, metal and fabrics, to ensure consistency from concept through delivery.
The spectral reflectance curve provided by a spectrophotometer is commonly known as the color’s “fingerprint” because it is as unique to that color as our fingerprints are to us. In addition to ensuring a color match, comparing the spectral reflectance curves between two measured colors, such as a color standard and a dyed sample, can help you identify metamerism, a phenomenon that occurs when two colors appear to match under one lighting condition (such as incandescent), but not another (such as daylight). If you’ve ever put on black socks using only your bed stand lamp for light, only to realize later in daylight that one sock is black and the other navy blue, you’ve experienced this phenomenon. Metamerism is a common color development obstacle in textiles when raw materials are sourced from different locations.
Types of Spectrophotometers
Two primary types of spectrophotometers are used in textile applications. To select the right one, you must consider your application and desired functionality.
0º/45º (or 45º/0º) – Ideal for measuring color on smooth and flat surfaces, this type of spectrophotometer measures light reflected at a fixed angle to the sample, usually 45-degrees. 45/0 instruments are considered “Appearance” instruments because their measurement results are influenced by surface texture and gloss, as well as color. For this reason, 45/0 instruments are typically only used on smooth textiles, such as the material used for screenprinting or digital printing on signage and banners. Traditionally, their main function in the textile industry has been sorting rolls of fabric in cut-and-sew factories to ensure homogenous color on single garments. Recently, small 45/0 devices are being used to identify colors in the field by comparing their measurements to known palettes, such as Pantone.
Now, with the increasing use of digital print on fabric, 45/0 instruments are used primarily for calibrating those digital textile printers to assure consistent color throughout the production run.
Some 0º/45º spectrophotometers are non-contact imaging spectrophotometers and include an on-board color camera to help characterize today’s more complex materials. The camera enables advanced image features that compensate for texture, gloss and other appearance effects for more accurate measurements of vinyl, carpet or fabrics. These imaging spectrophotometers can be used in color formulation and quality control operations. They are ideal for small and odd shaped samples, such as straps, elastics and other components of intimate apparel.
Typically, however, sphere spectrophotometers are the instrument of choice in textiles and apparel.
Sphere – Sphere spectrophotometers are the most common choice for fabrics, textiles, and digital textile printing applications because they illuminate the sample at all angles to create measurements that can be used to formulate a color that will be applied to many different substrates. Sphere instruments are commonly used for measuring the color of textured surfaces such as textiles, carpets and plastics, as well as shiny, highly glossy, surfaces.
Sphere spectrophotometers offer a number of features to help address complex color measurement requirements. For instance, their ability to measure in reflectance mode is recommended for opaque materials, while transmission mode can capture color on translucent or transparent materials, as well as quantifying opacity and haze.
Sphere devices can measure in both Specular Included (SPIN, SCI) and Specular Excluded (SPEX, SCE) modes, enabling the user to both formulate in the SCI mode and to compare the appearance of similarly colored substrates with different surface textures in the SCE mode. Specular Included negates the effect of surface variation — texture and gloss ― to only measure the color (ideal for formulating dyes and coatings). Specular Excluded conveys the surface appearance in the color measurement, making it the perfect tool for comparing similarly colored materials with different textures like leather and knit cotton/poly blends.
Portable vs. Benchtop
Spectrophotometers come in many shapes and sizes, from the practical, convenient portable spectrophotometer that is small enough to fit in the palm of your hand, to larger benchtop models designed for the most precise color measurement jobs.
Portable (also called handheld) devices are great for toting around the lab or production floor to spot check quality, or for taking on the go to measure color for inspiration and design. They can also be used in the field to capture color information for use in designs or for quality checks at supplier sites. Many portable instruments offer bluetooth connectivity to quality control software for immediate color analysis, while others can be plugged into a master computer to upload and download data.
Because they’re incredibly precise and consistent, benchtop devices are typically used to develop color specifications with strict tolerances. Top-level benchtop instruments have very tight inter-instrument agreement enabling color specifications and potential formulas to be e-mailed to supply chain partners, facilitating fast decision-making on digital lab dips to be done overnight.
Color and materials professionals who are dealing with brand and seasonal color palettes or manufacturing components that must match at final assembly rely on benchtop spectrophotometers to establish digital color standards, create color tolerances, formulate colorants and dyes, and assess whether fabric samples and production are within specification.
Other things that users may want to consider when selecting the right spectrophotometer include aperture size (benchtops can go bigger and smaller than portable sphere instruments), UV calibration ability (to control the fluorescent effect of optical brighteners and daylight fluorescing agents), and, of course, portability.
Which Device is Right for You?
Within the apparel and footwear industry, brand owners, designers, lab techs and quality control professionals incorporate spectrophotometers into their color management programs to ensure color remains consistent, from the time it’s specified in design until final quality check. One size does not fit all. To truly determine the best instrument for your color measurement needs, you must consider the type of materials you will measure as well as your job mix, need for portability, and tolerance requirements.
Bob Karpowicz is Color Solutions Project Manager, X-Rite and Pantone, and has more than 23 years of color management experience working with customers across printing, ink, textile, plastics and coatings industries. Bob is an active AATCC member and has taught a number of courses on the practical applications of color technology. X-Rite and Pantone are the global leaders in the art and science of color. Together they offer a full range of technology solutions for the specification, formulation, verification and production of color. For more tips on selecting the right spectrophotometer visit the X-Rite blog at https://www.xrite.com/blog. Twitter @xritecolor