Metamerism in Colors: Best Practices for Color Matching
Metamerism identifies the various appearances of a color. Industries such as interior design, graphic design, and fashion use metamerism for color matching. Metamerism also enhances color accuracy on computer screens and mobile devices.
What Is Metamerism?
Metamerism is when two colors look alike in specific lighting conditions. Metameric colors are non-identical but look similar to the observer when placed at an angle. For instance, two paint colors may look identical under artificial light but distinct in natural lighting.
What Causes Metamerism?
- Light sources: A light source emits various wavelengths of light that an object reflects or absorbs. The wavelengths reflected control the color we perceive on the object.
For instance, an LED bulb only emits red and blue wavelengths. An object would look darker than it appears outside under the sun’s broad spectrum.
- Variations in the viewing angle: Metamerism occurs when two objects only match if viewed from one angle. Colors change when an object shifts because the angle of incidence also changes.
- Observer’s view: People with trichromatic vision may see color differently due to age, brain judgment, and mood. Color blindness is also a leading cause of observer metamerism. An observer may be unable to distinguish between two shades and view them as similar colors.
- Combination of dyes or pigments on the object:
Dyes and pigments color textiles, plastics, rubber, automotive parts, paints, and more. Different dye types vary in reflectance.
Metamerism occurs due to improper mixing of pigments and using a non-identical base color on one pigment. When color matching, it’s best to view dyes under natural light, fluorescents, or LED lights.
Characteristics of Metamerism
- Color matching: Two colors with distinct spectral compositions may match under specific lighting and viewing conditions. It’s an essential aspect of colorimetry and applicable in the paint, textile, and printing industries.
- Spectral sensitivity: Our eyes have varying sensitivity levels to light wavelengths. It causes a difference in color vision when looking at objects and leads to metamerism.
- Dependency on lighting conditions: Metamerism relies on lighting for two colors to match. Two hues may look similar under artificial light but different in natural daylight.
- Color constancy: The visual system tries to maintain the perception of constant colors despite changes in lighting conditions. This can result in metamerism.
Examples of Metamerism
Paint colors show metamerism under specific lighting. A painter may perceive that the fresh, wet paint is the same color as the older paint when color matching. But, once dry, the new paint looks darker or lighter. For better clarity, paint manufacturers indicate the paint’s actual color on a sample swatch.
The difference in paint reflection under light causes metamerism in automotive coatings. The lighting environment in a garage causes a metameric effect on the paint, whereby different coatings look alike. The effect changes when the lighting environment shifts. Metamerism occurs since each pigment absorbs specific wavelengths (colors) of visible light.
Inkjet printers produce matching copies of text documents or photos by mixing colors under a light source. Users change the ink colors until they observe some metamerism in the original and copy documents. Colorimeters, spectrophotometers, and other devices help evaluate and match the ink colors.
Metamerism occurs when two dyed fabrics match under a light source but look different in other lighting conditions. It occurs due to the different spectral emissions of light sources. To minimize metamerism, textile companies use standard illuminants. They also perform metamerism tests to maintain consistent color quality in the textile industry.
Metamerism causes color discrepancies between digital objects. The limited color gamut on display restricts the color range produced, which results in a different output. Images may also look similar on one display but appear different on another. Color-calibrated displays can ensure accurate color representation across various lighting conditions.
The Perks of Metamerism in Color Matching
Metamerism simplifies color matching in various ways.
- Color accuracy and consistency: Metamerism reduces color mismatch by ensuring colors match under different lighting. It also helps maintain consistency in a product line.
- Cost-effective: There’s less need for many color samples under different lighting conditions.
- Ease of use: Metamerism allows designers and manufacturers to color-match design samples and product batches.
Common Problems With Metamerism
Illuminant metamerism is a barrier to color matching and compromises the final results. Identifying illuminant metamerism in the textile industry reduces waste and ensures consistency.
Metamerism also causes poor color reproduction in the printing industry. Using different inks and paper causes color shifts in the final product. As a result, the copy may look different from the original material.
When looking at metameric colors, our eyes perceive them differently based on the surrounding light. It can cause color misregistration when positioning colors in print, which results in streaks, smudges, and other defects in a printed image.
How to Make Metameric Matches
Determine the lighting conditions
When making metameric matches, consider the type of light source and color temperature. Adjust the intensity of light under which the colors will be viewed.
Choose a color space
A color space is a criteria for organizing colors. Cameras use color space for color profiling and reproduction. It helps determine if the second sample shows any contrasting metameric effects from the original.
RGB digital cameras are ideal for acquiring realistic images of colors. CMYK or CIE Lab color spaces provide more accuracy in printing.
Measure the samples
Using a spectrophotometer or colorimeter, measure the spectral reflectances of the color samples. The devices help predict metamerism in colors. The samples are metameric if the colors match under one light source but don’t for other light sources.
You can also use a Color Assessment Cabinet (CAC) to check the quality of the match using target lighting conditions. The viewing angle, material texture, and background colors affect the quality of metameric matches.
Metamerism vs. Color Rendering: What’s the Difference
Metamerism assesses the accuracy of a color match. It occurs when two objects match in color under one light source and differ in another source. Color rendering measures the precision of colors in an image.
It evaluates how a color appears when viewed from different vantage points. The evaluation is suitable for images with complex color palettes, such as those in product photography. A high color rendering index means a color is more realistic under a light source.