How to Accurately Analyze Carpet Color Using the UltraScan VIS Spectrophotometer

The Ultra-Scan VIS can accurately measure carpet color because it takes texture into account. Image source: Pixabay user Frantisek_Krejci

A hotel chain has hired an interior designer to replace the old carpet design in every guestroom with something that looks more sleek and modern. After sifting through a number of swatches, the designer finds the perfect shade: a simple charcoal grey design that will contrast beautifully against the crisp white comforters and bed sheets that the hotel uses. But in order for the interior designer’s vision to truly come to life, the carpet color needs to be consistent from room to room. Not only does every guest room have to match, the hotel also needs to ensure that the carpeting looks seamless from the entrance of the room to every corner. If the hotel receives rolls of carpeting that vary in color even slightly, it will make every seam more obvious–the hotel will end up with a room that looks more like a patchwork quilt than a chic, modern space (commonly referred to as a “carpet sidematch problem”).1

This is just one of many reasons carpet manufacturers should take accurate color measurements of their products before releasing them on the market. However, it isn’t always easy to measure carpet color, even when you use color measurement tools like spectrophotometers. Because carpeting is soft, uneven and not always entirely opaque, analyzing the color of your samples can be frustratingly complicated. An instrument such as the UltraScan VIS, however, simplifies this process by allowing for optimal measurement methodology and the highest degree of color measurement precision. Unlike many other spectrophotometers on the market, the UltraScan VIS instrument is specifically designed to measure carpeting (among many other sample types), and makes the color quality control process fast, simple and extremely accurate.  

The Challenges of Analyzing Carpet Color

Carpet swatches seem easy to analyze at first glance, especially when designs feature just one solid color. However, carpeting is never truly “solid” in color, even if it appears so to the naked eye. If you look carefully at any carpet swatch, you’ll see that the tiny particles that make up the sample frequently vary in opacity, shape, and color. These three factors pose a number of challenges for manufacturers.   

Challenge #1: Opacity

Opacity is one of the first challenges you’ll come across when you try to measure the color of your sample using a spectrophotometer. Many carpet products are slightly translucent, and this becomes more obvious when you change the backing of your sample. For instance, your slightly translucent carpet sample will look lighter when backed by a light-colored background, but that same sample will appear much darker when backed by a dark-colored background. In order to get an accurate measurement, you have to standardize your sample backing.

Challenge #2: Shape

Carpeting isn’t flat. Rather, the material is flexible, and the tiny threads that make up the sample can shift with even the slightest pressure. The non-homogenous nature of carpeting makes it difficult to measure color unless you use tools specifically designed to handle textured samples. When a color measurement instrument presses into a carpet swatch, it creates a pillowing effect. The tiny carpet particles bend around the instrument’s measurement port, and this in turn can cast shadows that alter the overall color reading. To fix this, you need to take several readings in succession, then average those readings to get an accurate measurement.

Challenge #3: Color

Finally, the color of your sample or the type of dye that you use can cause a few unexpected problems for color measurement instruments. The most common problem that you may come across is the use of fluorescent dye in carpeting. This dye makes the product appear brighter and whiter than it is, and it is frequently used in white carpeting.2 Although this dye makes your products look whiter and potentially more appealing, it also makes your samples more sensitive to UV light. When your sample is exposed to the UV that naturally occurs in your light source, it can alter the overall measurement result, making your product appear lighter. This is why you need to cancel out the impact of UV on your sample or take UV into account when you measure your product’s color.

Pile heights and texture can significantly affect the appearance of your carpet samples. Image Source: Unsplash user Dane Deaner

How the UltraScan VIS Overcomes These Challenges

The UltraScan VIS takes all three of these challenges into consideration. First, to overcome variations in opacity, the instrument helps you standardize the environmental conditions of your lab or test space. It comes equipped with a port insert and light trap that can be newly standardized for each sample that you measure, ensuring that every sample is backed properly and that the environment isn’t making the sample appear lighter or darker than it really is.

The instrument also operates in multiple modes; the reflectance-specular excluded mode (RSEX) works well for semi-transparent and opaque samples alike while allowing you to take texture into account. For instance, if you were measuring a high-pile carpet, then the color will likely appear slightly different compared to a low-pile carpet of the same color.3 By measuring the difference in appearance between these two samples, you can get a more accurate read on every product you manufacture.

The UltraScan VIS also overcomes variations in shape and carpet texture by offering multiple measurement options. You can clamp your sample into place and take your first color reading. Then, the instrument allows you to rotate the sample 90° and move it to a different area of the swatch. You can repeat this process as many times as you would like. Once you have several different measurements, you can average these readings, which, in turn, reduces the problem of measurement variation in non-homogenous samples. You’re not just relying on a single reading of your sample, but on multiple readings that will give you the whole picture.

And finally, the UltraScan VIS allows for accurate measurement of fluorescent or optically samples. The instrument is capable of compensating for the effects of UV lighting on a sample using UV control. The instrument can simulate D65 illumination using  a UV control filter by calibrating using an optional fluorescent standard. By fully inserting the filter, you can completely eliminate UV energy from the measurement, or, alternatively, you can measure the impact that UV has on the sample by measuring the carpet swatch both with and without this UV filter fully inserted.

To accurately measure carpet color, you may need to take multiple measurements and average your findings. Image Source: Unsplash user Stef Versoza

Using the UltraScan VIS

To use the UltraScan VIS to measure your carpet samples, start by configuring the instrument’s software to your desired color scale, illuminant and observer. For instance, if you’re measuring an optically-brightened swatch of white carpet, then you can calibrate your instrument for the D65 illuminant using the fluorescent standard. Once the UltraScan VIS is properly calibrated and standardized, you can begin the measurement process. Cut out a small sample of carpet from a roll, ensuring that your sample is large enough to cover the entire port insert on the instrument. Hold your sample in place using a sample clamp or a compression clamp –the compression clamp is most often used for carpet samples. After your sample is firmly in place, you can take your first color reading. Then, you may choose to rotate your sample, measure in a new area, and repeat this process as needed, or you can stick with a single measurement. If you make multiple measurements, take an average of these different measurements to get one single color result. These readings can be stored for recall at a later date to compare with new batches of the same color carpet, ensuring color accuracy and consistency throughout production.

HunterLab Dependability

With more than 60 years of experience in the color measurement industry, you can rely on HunterLab products to provide you with the most accurate measurements possible. Although our instruments all have unique features, they include the same dependable and accurate design at their core. We focus on cutting-edge software, hardware, and the latest advances in technology to ensure that all of our instruments meet the highest standards. Contact us learn more about the UltraScan VIS or any other spectrophotometer in our renowned product line.