The Effect of Texture: Ensuring Accurate Colour Measurement Through Integrated Height Measurement

Texture variation can present special challenges for accurate colour measurement. Image Source: Flickr user Les Chatfield

Over the past few months, I’ve been renovating my house, and while the structural design elements came easily, I struggled with choosing a colour palette. After looking through hundreds of photographs of kitchen cabinets, I finally found something I could imagine living with for the next 10 years and downloaded a colour identification app to find out the name of the colour. The app lets you pinpoint an area of an image and analyzes the pigment to come up with an exact colour match from a particular paint brand. It sounded simple. But when I began using the app, its limits quickly became clear; the further the cabinets were from the light source, the darker the colour appeared, leading to a seemingly limitless range of potential options. How could I be sure that the area I was selecting represented the true colour I was looking for?

Manufacturers of consumer and industrial goods face a similar dilemma when it comes to colour measurement: how do you obtain accurate readings when texture affects how light acts on different areas of a sample?

The Problem of Texture Variation

Texture variation in consumer and industrial goods presents special challenges for colour measurement; the peaks of the sample appear lighter than the valleys as the depth of field alters our perception of colour. This creates problems for gaining consistent colour measurement not only within a sample, but between samples. Traditional time interval-based laboratory testing may erroneously flag colour variation between two identically pigmented samples due to differences in texture. For example, two pieces of embossed vinyl siding may, in fact, both be within spec, but a heavily textured portion of the siding may appear to be darker than a portion with less embossing. If an operator neglects to press the samples flat prior to testing and does not account for texture variation, they may then scrap good product and make unnecessary changes to the production process to compensate for a phantom issue, throwing future products out of spec and creating costly waste.

Traditional colour measurement of powders can require labor-intensive sample preparation to optimize sample uniformity. Image Source: Flickr user Dave Fischer

Room for Human Error

In some manufacturing processes, operators may try to minimize variation by using strict sample preparation guidelines to maximize uniformity or taking multiple readings to avoid texture interference. Powders, for example, may be arranged to a specific density and height prior to testing in an attempt to create consistency within and between samples. In the case of textured plastics, operators may be required to press the sample flat and take three readings, rotating the sample 33 degrees between each reading, and averaging the results in an attempt to compensate for texture. However, these are labor-intensive processes and depend on predictable operator behavior, opening the door for human error and leaving the production line vulnerable. Even slight differences between the sample preparation habits of operators may jeopardize the accuracy of the colour measurements and create inconsistencies within the finished product.

Integrated laser height measurement can compensate for texture variation to ensure accurate and consistent colour measurement. Image Source: Flickr user Randy Aquilizan

Integrating Height Measurement in Spectral Analysis

How, then, do you ensure consistent and accurate colour readings in non-uniform materials? HunterLab offers an elegant solution in the form of spectrophotometric instruments with integrated laser height measurement capabilities that take quality control to the next level. The embedded laser continuously analyzes sample height and uses a unique algorithm to compensate for texture variation, optimizing colour monitoring precision. Integrated height measurement minimizes the risk of human error, can eliminate the need for precise sample preparation, and can account for variation in sample presentation. By seamlessly incorporating colour and height measurement in production lines, manufacturers can decrease reliance on labor-intensive testing processes, minimize scrap, and realize significant cost savings.

For over 60 years, HunterLab has led the way in colour measurement innovation. Our products represent the pinnacle of technological innovation in the field of colour quality control and were developed in response to the diverse needs of our customers. Please contact us today to learn more about how HunterLab instrumentation can meet your colour measurement needs.