The Colour That Changed Under the Shop Lights
A student designs a two-tone tunic: a deep teal bodice in a silk-cotton blend and a mustard-yellow skirt in a cotton-linen blend. She chooses the colours from a magazine photograph and buys the fabric in the shop under warm tungsten lighting, where the two colours look rich and harmonious. At the school fashion show, under cool white LED stage lighting, the teal reads almost black and the mustard looks muddy brown; the two tones clash. She also finds that the mustard skirt has gone patchy after she spot-cleaned a mark with a household bleach-based spray. She has three days before the show and no budget for new fabric.
1. Explain why the colours appeared so different under the two light sources, using colour theory and the idea of metamerism.
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Colour is not a property of the fabric alone; it is the result of a light source, an object and an observer together.
Light source differences. Tungsten light is warm, with a strong output in the red-orange part of the spectrum and little blue. LED stage lighting is cooler and often has a spiky spectrum with a strong blue peak and weaker red. A teal that reflects blue-green looks rich under tungsten because the warm light lifts the red component of the blend, but under cool LED the same fabric reflects mostly blue-green with little red to lift it, so it appears darker and closer to black. Mustard reflects yellow-orange; under a blue-rich source there is less yellow-orange light to reflect, so it looks brown and dull.
Metamerism. Two colours that match under one light but not another are called metamers. The silk-cotton and cotton-linen blends have different fibre lusters and dye uptake, so their reflectance curves differ even though they looked harmonious in the shop. The shop's tungsten light hid that difference; the stage LED exposed it.
Lesson for design. Always check colour combinations under the lighting of the final venue, and in daylight, before committing to fabric.
2. The mustard skirt is patchy from the bleach spray. Propose a three-day rescue plan that uses no new fabric and addresses both the colour clash and the patchiness.
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Day 1 - assess and stabilise the patchiness. The bleach has removed dye unevenly. Do not apply more bleach. Wash the skirt thoroughly to remove residue, then assess in daylight. Options, in order of risk:
- If the patches are faint, overdye the whole skirt with a cold-water cotton dye in a deeper mustard or rust tone. This unifies the patch and shifts the colour.
- If patches are strong, disguise rather than correct: add a decorative band, appliqué or tie-dye effect that intentionally breaks up the surface.
Day 2 - resolve the colour clash. Since teal and mustard fight under cool light, change the relationship rather than the fabrics. Add a separating element at the waist - a wide sash or belt in a neutral (cream, charcoal or black) - so the two colours no longer meet directly. Overdyeing the skirt toward rust or terracotta also moves it closer to teal on the colour wheel, reducing the clash.
Day 3 - test under the real lighting. Take the finished tunic to the stage or a similar LED setup and check it. Photograph it under both cool and warm light. Adjust accessories, not fabric.
Record the outcome in the portfolio: the original swatch choice, the lighting test, and the rescue decisions, with photographs as evidence of evaluation.