By Paul Uglum, president, Uglum Consulting, LLC
The purpose of plastic decorating is to add value to the object being decorated. This value can take the form of appearance, improved function capability or increased durability. When thinking of appearance, color often is the first characteristic that comes to mind. There is, however, another very important characteristic, and that is texture. Texture can impact the visual, functional and tactile properties of a product.
One definition of texture is “having a rough, uneven surface.” A better definition is “the visual or tactile surface characteristics and appearance of an object.” These are not overly impressive descriptions of a very important characteristic. In plastic decorating, a more useful definition is “the three-dimensional characteristics applied to plastics as a part of the decorating process.” This texture can be very fine or pronounced, depending upon the technology and desired outcome.
The obvious questions are: Why is it important? And, how can it be used to add value to the part being manufactured? In plastic decorating, texture often is used to enable the plastic-decorated part to more closely match the appearance and feel of natural materials, such as wood, or manufactured surfaces, such as carbon fiber or brushed metals. Beyond mimicry, textures can create attractive and complex high-tech appearances.
Textures also can be used to create a visual and tactile experience that increases the desirability of a package or product. Because of this, texture is an integral part of plastic decorating in many applications ranging from high-end automotive interiors to disposable product packaging.
Texture has a significant influence on the visual appearance of a decorated part. Among other things, the texture impacts the gloss and appearance of a decorated product and can change the apparent color. Fine texture creates a lower gloss appearance and makes the color appear lighter than a part with no texture.
The Psychology of Texture
The psychology of texture is about how individuals react to the physical objects they encounter in daily life. It is about how value is perceived, and how texture enhances that perceived value. In the case of wood grain or leather appearances, the perceived value often depends on how well the decorated surface replicates the appearance and feel of the real material. The quality of the decoration directly influences how an object is valued.
John Bargh, a psychology professor at Yale, has conducted a series of experiments showing that tactile experiences affect people’s judgments and decision-making. Marketers make use of this haptic psychology to design packaging that is more appealing. There is a tendency for people to value something more highly once they have made contact with it; as a result, the use of embellishments and texture is an effective marketing tool for packaging. Touch influences decision-making in ways people do not perceive. To quote Thomas Fuller from 1732, “Seeing is believing, but feeling is the truth.” Objects that individuals have touched often seem to possess greater value and desirability.
Decorating Technologies
Many plastic decorating technologies can be used either alone or in combination to create desirable surface finishes, including textures. In choosing the right technology for the application, the first step is to define the expected outcome and then select the process that best meets the desired characteristics.
Molded Texture
The simplest way to decorate a part is not to decorate it, but to have a finished part when the molding process is complete. Advances in texturing, using chemical etching and laser surfacing of the molding tool, allow complex and varied textures to be applied directly to the molded plastic part. Molding techniques such as injection compression molding and dynamic temperature control technologies allow precise transfer of the texture to the surface of the part. These technologies have been used very effectively in automotive applications to produce parts that feature both high gloss and finely textured low gloss in the same part.
Coatings and Plating
Coatings create a variety of issues when it comes to texture. By their nature, they tend to wash out or completely cover fine, molded-in textures. They can be used effectively with more pronounced textures. Although it is possible to create a texture using coatings, it often is less effective and the result is more variable than with other techniques. Similarly, galvanic plating tends to modify texturing. Some platers have developed processes that enable plated surfaces to have complex and repeatable appearances.
Direct Laser Structuring
Direct-to-part lasering is a versatile and effective means of creating a decorative textured surface. Rayn Technologies has developed techniques that can impart texture directly to both as molded plastic and painted parts. Their technology allows laser ablation and texturing over large surfaces and three dimensions (see Figure 1).
Several significant advantages result from this innovation. First, it is a green technology; it does not involve the addition of any chemicals or process steps. It can be used in combination with laser ablation (complete removal of a layer of paint) to create complex surface appearances that can include backlighting. Because it is digital, it can be used to create mass customization of the product if needed. Using this technique, it is possible to precisely position the patterns across adjoining parts (see Figure 2) in a way that is not possible with processes such as hydrographics.
Hydrographics Texturing
The standard hydrographics process consists of an ink transfer in water, followed by cleaning and a top coating. This can create the visual effect of a textured surface. The Cubic division of Taica has developed two processes to impart a texture to the finished part. The S-Cubic process uses the standard process. The E-Cubic process starts with ink transfer in water followed by UV curing, cleaning and drying. This green process does not require a clear coating. Both are capable of achieving a variety of different three-dimensional effects, including wood grain that gives the look with the feel of real wood (see Figure 3), fine hairline patterns and geometric patterns.
Inkjet Structure
The process of inkjet direct-to-part decoration continues to technically advance and gain popularity. Inkjet is capable of much more than photo-quality woodgrain, stone and abstract textures; it is capable of providing tactile finish options as well. As a digital process, it has a wide range of capabilities and is very scalable. The primary limit still is the distance between the print head and the decorated object.
Inkjet increasingly is being used to create printed laminates in the furniture market. It can create photo-quality woodgrain and stone directly onto surfaces and can be finished with haptic effects, such as embossing. This creates surfaces that are indistinguishable from the real materials and often are more durable. Another application of texture is signage where braille features can be included for the visually impaired.
In-Mold Decorating
In-mold decorating (IMD) is not one, but a family of decorating processes that complete the plastic decorating during the molding process. The processes range from ink transfer to in-molded decorated appliques. In-mold decorating is one of the most versatile decorative processes and has long demonstrated its ability to go far beyond cosmetic decoration alone.
In-mold decorating also is capable of wood grain patterns, complex high-tech patterns and slightly raised surfaces, as well as the creation of multiple images and textures in the same part (see Figure 4). IMD particularly is capable of providing the appearance of texture using printed layers to mimic the appearance of textured surfaces and incorporating such features as holograms (see Figure 5). Beyond automotive applications, textured in-mold decorating has been very successful in the cosmetics industry and home appliance market.
Similar to in-mold decorating, thermal transfers also are capable of producing textured surfaces. Metallic surfaces that have been nickel-brushed are good examples of thermal transfer capability.
In-Mold Actual Materials
Authentic materials and surfaces are required in some high-end applications. To meet this need, actual materials – such as wood, metal and fabric – can be insert molded. While these provide natural texture, they are limited in durability and by the design constraints required for the materials to be successfully processed. In most cases, they also are significantly more expensive to produce.
Functional Textures
Textures can be used to convey information and provide guidance. An example would be a change in texture that helps to identify the location of embedded capacitive switches in automotive control panels.
Recent work has demonstrated that a texture can be both visually interesting and functional. Generally, these are finer textures or patterns. A number of the functional textures are based on biomimicry; they copy patterns found in nature.
A team at the University of Nottingham has found that patterns drastically can reduce bacteria’s ability to multiply on plastics. This is significant for medical devices. The researchers studied more than 2,000 different shapes and found that microscale shapes can support or inhibit bacterial attachment and the resulting biofilm formation. This functionality was found to be independent of the type of material and is a function of the shape and spacing of the features.
Another technology, Sharklet, is based on the structure of a shark’s skin, with micrometer-sized ribs that, when aligned with the direction of fluid flow, reduce drag by 8%. This can reduce fuel consumption in boats and airplanes, increase power output from wind turbines by 5%, and create quieter, more efficient propellers. Sharklet also has been found to inhibit algae growth and biofilm formation.
Nano textures have been used effectively to reduce dirt buildup on structures, such as solar panels. Textures even have been used to create optically functional surfaces. Moth-eye structures have been used to create anti-reflective surfaces in displays. In another application, micro lenses have been printed on surfaces.
Some of these structures are at the edge or just beyond what can be done with current decorating processes, but can be useful in future designs with more development.
Measuring and Characterizing Texture
As with any decorated part, a visual evaluation of textured surfaces always is the most important. With a texture, it is important to control the lighting and view the part at various angles to pick up subtle changes. Although touch also is an important evaluation, tactile sensitivity significantly varies from person to person, so it is hard to quantify. For instrumental measurements, traditional surface roughness parameters like Roughness Average (Ra), which is the average deviation from the mean line, or Engineered Roughness Index (ERI), calculated from micro topography dimensions, do not adequately describe the range of decorative textures.
Geometric details, density, periodicity, symmetry or the hierarchical arrangement of surface features are all important. With fine features or variable surfaces, interferometric microscopy provides the best system to view and understand the surface. It can provide both an image of the surface and measurements of surface characteristics. Given the variety and complexity of decorative textures, a working sample probably is the best standard and the best means of communication.
Issues with Textures
Textured surfaces have some issues that smooth surfaces do not. They can be subject to increased wear. Fine textures can tend to mar as features are deformed. On the other hand, texture can hide some level of quality variability in decorated parts.
Depending upon the structure, textured surfaces trap more dirt over time and can be more difficult to clean. Having a surface roughness or discontinuity is not always desirable and can be an indication of various defects or failure to properly decorate an object. Textures caused by unintended features, such as splay or sink, can indicate problems with materials or processes.
Conclusion
Texture is a useful and sometimes neglected aspect of plastic decorating. Effective use of texture in decorated plastic can be tactile, visual, functional or all three. If thoughtfully considered during the product design, it can significantly impact both the aesthetic and functional value of the finished part. Like all features, it has to be planned for and designed into the finished product.
References
- Kevin Abergel, The Tactile Tipping Point: Reviewing the 2025 Whattheythink / Taktiful Digital Embellishment Study, Technology Outlook, Issue 2025
- Manuel Romero, et.al., Combinational discovery of microtopographical landscapes that resist biofilm formation through quorum-sensing-mediated autolubrication, Nature Communications (2025)16:5295
Paul Uglum has 43 years of experience in various aspects of plastic materials, plastic decoration, joining and failure analysis. He owns Uglum Consulting, LLC, working in the areas of plastic decoration and optical bonding. For more information, send comments and questions to paul.a.uglum@gmail.com.