Exploring How Spectrophotometric Analysis Can Enhance Colour Consistency in Ceramic Tile

New technologies are enhancing colour consistency in ceramic tile via algorithmic colour formulation. Image Source: Flickr user Living Rooms London

Ceramic tiles are one of the most versatile and widely used building materials in existence. Both practical and decorative, these tiles can be incorporated in a multitude of ways within both residential and commercial structures, where they adorn everything from walls to floors to ceilings. With the surging interest in home decorating and renovation, consumers are more willing to experiment with unique shapes and colours than ever before.

But as interest has grown, so too have aesthetic standards, as consumers expect both a wide variety of colour and colour consistency in ceramic tile production. UV spectrophotometric analysis of emerging colour formulation technologies is playing an essential role in expanding and enhancing the variety and quality of colour, helping researchers create new and improved methods of controlling the look of these functional and often beautiful products.

While colour formulation algorithms have become standard in many industries, ceramic tile production presents special challenges for implementation of this unique technology. Image Source: Flickr user DuPont Surfaces

The Benefits and Limits of Algorithmic Colour Formulation

In an effort to increase the efficacy of production, accuracy of coloration, and precision of colour matching, many industries—including paper, plastics, and textiles—have turned to algorithmic colour formulation. These algorithms expand colour selection using a minimal number of pigments, enhance colour matching abilities, and reduce waste by allowing manufacturers to prepare only the exact quantity of mixtures required. Until recently, however, colour formulation algorithms have largely failed to translate to the ceramic tile industry, due to the unique characteristics of ceramic material itself:

The most important is connected with thermal and chemical stability that pigments must have towards the molten glass developed during the firing cycle at high temperature: the same pigment, in fact, can develop slightly different colours depending on both firing temperature and chemical composition of glaze and ceramic body to colour.1

Colour variation in the tile body, grain size distribution, firing process variations, and interactions between pigments and glazes all contribute to the unpredictability of colour development.2 Unfortunately, the very same attributes that present challenges to algorithmic colour formulation are the very reasons such methods would be so advantageous to the ceramic tile industry; incorporating algorithmic technology would diminish unwanted batch to batch and lot to lot colour variations, producing more stable coloration to satisfy consumer demand.

Refinement and application of new colour formulation algorithms could not only improve colour consistency and quality in mass ceramic tile production, but facilitate historic restoration and small-batch reproduction. Image Source: Flickr user Metro Centric

Spectrophotometric Evaluation of Colour Consistency in Ceramic Tile

In 2006, however, a group of researchers developed an effective colour matching algorithm for ceramic tile using the Kubelka-Munk theory verified via UV spectrophotometric evaluation. In a study published in the Journal of the European Ceramic Society, the researchers developed a system of four industrial pigments that served as the basis for formulation. By applying the principles of the Kubelka-Munk theory, they were able to create an efficient algorithm for the formulation of ceramic tile pigments. Five target colours were analyzed using a UV spectrophotometer and their reflectance spectra compared to the Natural Colour System standards to determine colour accuracy.

These spectrophotometric measurements not only allowed the team to determine the efficacy of the algorithm, but also correlate colour to process variables. “The decisive steps have been the introduction of a base glass in the formulations and the characterization of the colored glazes after firing,” they note. Furthermore, the method revealed predictable colour differences based on firing temperature variation, suggesting that carefully modulated temperature controls could significantly enhance colour consistency.

Further development and widespread implementation of such colour formulation algorithms could increase quality, variety, and consistency in mass ceramic tile production while helping tile manufacturers increase efficiency and realize cost savings. At the same time, it could also facilitate partial tile replacements as well as historical preservation, restoration, and reproduction by allowing for precise colour matching and economically viable small-batch or even one-off production.3 UV spectrophotometry will continue to play an integral role in the development and evaluation of any new algorithmic technologies, owing to its high degree of accuracy, versatile optical geometries, and precise, objective quantification of colour information.

HunterLab Colour Measurement

HunterLab has been a pioneer in the field of colour measurement for over 60 years. During that time, our instruments have helped researchers and manufacturers develop and deploy new technologies that enhance colour formulation and production processes across industries. Today, we offer a complete range of portable, benchtop, and in-line spectrophotometers engineered to give you unprecedented insight into colour behavior and expanding your ability to collect, analyze, and share colour information. Contact us to learn more about our line up of colour measurement instruments, customizable software packages, and world-class customer support services.