The ITMA textile show saw an explosion in fade-resistant ink technology, but how does this phenomenon work?
By Vince Cahill
Colorants, sometimes called “chromaphores,” are molecules that cause color to reflect from dyes and pigments. A chromaphore is a group of atoms and molecules with alternating single and double bonds. Imagine this: When white light strikes a chromaphore, electrons within its atoms absorb photons with specific wavelengths. We see the other photons – those vibrating at wavelengths the electrons aren’t tuned to absorb – reflected as color.
In addition to oxygen and ozone in the air, UV light energy, which is part of sunlight, can break the chromaphore’s conjugated chain. When this happens, the chromaphore can no longer absorb photons, and it begins to reflect white light. We typically describe this visual effect as fading, a common problem to any printed materials exposed to sunlight.
Printed dyes in inks are exposed as vulnerable individual molecules. Pigment particles, on the other hand, cluster in groups of 10,000 or more chromophores dispersing UV energy over a larger mass, thereby protecting most of the chromaphores in the pigment particles from exposure to oxygen and ozone. See the benefit?
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