Visual color matching

Color-order systems, such as the many MunseU collections available from Macbeth, have been described previously. Essential for visual color matching is a color-matching booth. A typical one, such as the Macbeth Spectrahte, may have available a filtered 7500 K incandescent source equivalent to north-sky daylight, 2300 K incandescent illumination as horizon sunlight, a cool-white fluorescent lamp at 4150 K, and an ultraviolet lamp. By using the various illuminants, singly or in combination, the effects of metamerism and fluorescence can readily be demonstrated and measured. Every user should be checked for color vision deficiencies. 

Successful visual color matching requires a good understanding of the nature of color, how color is perceived, the influence of the physiological and psychological processes of color perception, the human element variability, and the ability to evaluate or assess an individual s color acuity. Next, it is important to define and... 

The condition of the standard is equally important. Is the standard dirty Does it have fingerprints on it Is it scratched or physically abused Is the color standard old Try to obtain another color standard if the answer to any of these questions is yes. A current, clean, well-cared-for standard is essential to a successful visual color match. It then becomes equally important that the color standard be stored under optimum conditions. These include storing in the absence of all light in a clean, dry environment away from heat along with careful minimal handling, even to the extent of handling only with clean, soft, cotton gloves. 

Is the color standard based on the same material as the desired match demands The color match becomes very difficult if the color standard is based in a plastic material that is different from the desired match plastic. A Pantone standard, an opaque painted paper, is still frequently used as a color standard. However, a Pantone paper standard does not address the issues of opacity, gloss, and texture, which are essential to color matching plastic materials. Similarly, painted metal color standards possess gloss levels that often exceed the range capable for most polymers. This factor also further complicates a visual color match in plastic materials with lower gloss. Thus, if possible, secure the color standard in the same material that the match is desired. 

It is very important to understand the plastic material before starting a color match Know the polymer, its limitations, processing conditions, physical properties, and other attributes. The more information known about the polymer, the more assured and defined is the visual color match. 

There are many available methods for mixing colorants into plastic materials. Choosing a laboratory method that will most closely match the production process is ideal, but not usually the norm. Colorant dispersions in plastic materials determine the perceived color. Thus, choosing a consistent, reliable mixing method that closely mimics production dispersions is critical to a good visual color match. 

The science of visual color matching is defined as the processes involved in achieving the match requirements, limitations, applications, performance, and processing in a final visual color match. Each step within this process must be clearly defined... 

This example shows the influence of primary colorants and their secondary effects in the visual color match of a gray color. A gray match trial appears visually dark, green, and blue relative to the color standard, but the opacity is satisfactory. The... 

---