When designing silicone rubber components to fit your product needs, many questions have to be answered. One of the aspects to consider will be the color or colors implemented so that your product stands out in the market. Knowledge of color models and how colors interact is imperative, as well as technology for successful color matching and production of custom silicone rubber keypads.
All colors are basically made up of three colors, known as the primary colors. The human eye has three different types of color sensitive receptors, called cone cells. Each cone receives a different wavelength of light. Blue is the short wavelength, green is the medium wavelength and red is the long wavelength. We set values to each to describe a color. These values are known as the “Tristimulus” values of a color. These tristimulus values can be conceptualized as the amount of the three primary colors in a tri-chromatic additive color model. The values are given in X, Y and Z values.
A Tristimulus colorimeter (Chroma Meter) is a device for measuring the reflected and transmitted color of objects. The illumination method employed illuminates the specimen from all directions using illuminants with almost equal brightness, and receives the reflected light vertically from the specimen surface. When looking at a color in general, multiple light sources and the light reflecting from the walls create diffused lighting conditions. Outside conditions from the sky are also considered diffused light. With a Chroma Meter and a flat specimen, the diffusion of light is eliminated. This gives the device control over the intensity of light being emitted and comparing that with light reflected.
There are many models for transforming the values given into an actual color. In the Hunter 1948 L, a, b, now known as “CIELAB,” color space deviates from the CIE (XYZ) in that the coordinates are based on a square root transformation of the color data, as opposed to a cube root transformation of the data. The Lab color space formula was specifically designed to accurately map color perception and compute more easily, which makes it more perceptually uniform than XYZ. Perceptually uniform means that a change of the same amount in a color value should produce a change of about the same visual importance. In custom silicone molding production, this can be especially useful for creating custom colors and matching existing colors, with an extremely high degree of accuracy.
The L component represents the luminosity, or black (0) to white (100) value of the color. Each whole number is categorized as a Delta E, which is a single number that represents the distance between two colors. The A and B components are further categorized into positive and negative values. The A component specifies the amount of green (-A) or red (+A), ranging from -120 to +120. The B component specifies the amount of blue (-B) or yellow (+B) ranging from -120 to +120. The ratio of these three components describes the color being produced. When producing a new color, using these values helps to determine which colors to add to offset other colors, with excellent precision to reach the exact color needed. Once the color is acquired, all of its values are recorded and stored for future production.
These readings are also useful in periodically checking the color of the parts being produced to maintain a constant color throughout the production process. All colors being matched are to be within one Delta E, which is well beyond the industry standard and not distinguishable by the human eye. This is then recorded and signed off on to continue production.
When designing custom colors into your products or replicating colors already in use, SiTECH’s highly trained color technicians can produce a wide array of color options with high precision and accuracy to fit almost any need. The colors can be made into pigment for use with our advanced silicone injection molding. They are also made into inks which we use to print a multitude of designs onto silicone rubber to meet your product needs. We also employ the latest in color detection and matching technology to provide you with the highest quality and repeatable results for the life of your product. You can rely on the experience and reputation that SiTECH has to offer for all of your custom silicone molding production and custom color needs .