Metamerism

Definition and Overview

Metamerism is a color-appearance phenomenon caused by differences in the spectral reflectance characteristics of dyes, pigments, and similar materials. In environments with different spectral distributions of light, such as daylight, store lighting, incandescent light, or white LEDs, color differences may become noticeable.

The weave structure, thickness, sheen, and fuzz of a textile also affect how it looks, but metamerism itself is not a term for a specific material or fabric type. It can also be an issue with combinations of fabrics and trims that look the same color.

Effect on Appearance

Main fabric, lining, sewing thread, zipper tape, buttons, and other items selected as the same color number may look matched in the place where they are checked, but appear different at the point of sale or in the wearing environment. In particular, with colors that are close together, even a slight difference can stand out.

Glossy materials, brushed materials, and sheer materials are also affected by light reflection and the underlying material. For that reason, it is important to distinguish between differences caused by metamerism and differences in appearance caused by surface shape and texture.

• Fabric and trims appear mismatched depending on the lighting
• Seam changes and stitching within the same product stand out
• No issues are found during daytime inspection, but differences appear under store lighting

Main Applications and Management Situations

In apparel, this should be considered for all items that use color coordination or matching of the same color. In particular, for products such as jackets, suits, uniforms, and formalwear, where the main fabric and multiple trims are matched in similar colors, checking from the planning stage is effective.

Although the season itself is not a cause, caution is needed in applications that are likely to be viewed under both outdoor daylight and indoor artificial lighting at night. Check not only the fabric itself, but also the secondary materials that will actually be combined with it.

Selection and Handling Notes

For color matching, assume the lighting conditions under which the final product will often be viewed, and check the fabric and trims together under multiple light sources. If possible, checking with a sample of a larger area or a sewn sample, not just a small swatch, makes it easier to judge differences in seam changes and stitching.

Metamerism is not a phenomenon caused directly by shrinkage, washing, or sewing. However, if the color relationship changes due to fading, color transfer, or lot differences caused by washing or sunlight, differences in appearance may become more apparent. Washing fastness and light fastness should also be checked separately.

• Share the inspection light sources as part of the approval conditions for color swatches
• Check combinations of fabric, lining, interfacing, thread, zipper, and more
• When producing additional quantities, recheck with the possibility of a different lot in mind
• Do not confuse color matching with fastness evaluation

Difference from Similar Terms

Fastness is a quality characteristic that indicates how resistant color is to changes or transfer from washing, rubbing, perspiration, light, and so on. Metamerism, by contrast, is a phenomenon in which the matching relationship between two colors appears to change mainly due to differences in the light source, so the object of evaluation is different.

A lot difference is variation in color, hand, and similar properties due to differences in production time or production unit. If there is a lot difference, color matching becomes difficult, but even within the same lot, color differences may appear depending on the light source.

Frequently Asked Questions