Meaning
Chemical compounds added to substrates or coatings absorb ultraviolet radiation and re-emit it as visible blue light. Manufacturers use optical brightener agents to make paper and textiles appear whiter and more vibrant to the human eye. These additives compensate for the natural yellowing of fibers and improve the contrast of printed images.
They are common in high grade office paper and premium retail packaging.
Chemical Additive
Molecular structures within the compound interact with the invisible portion of the light spectrum. The concentration of optical brightener agents determines the level of brightness achieved in the final product. Overuse can lead to a bluish tint that may interfere with color matching for branded assets.
Suppliers must monitor the addition of these chemicals to maintain consistency across production lots.
Fluorescence Effect
Viewing materials under different light sources reveals the activity of the brighteners. When optical brightener agents are present, a surface will look different under daylight than it does under standard office lighting. This shift creates challenges for color measurement because many spectrophotometers require specific filters to account for the fluorescence.
Inconsistent application of these agents results in variations that are visible when products are displayed side by side. Calibration of printing equipment must account for the specific excitation wavelengths of the additives.
Material Stability
Exposure to intense light over time causes the fluorescent effect to diminish as the molecules degrade. Because optical brightener agents are more sensitive to uv light than many pigments, the background color of the material may change before the ink fades. This degradation can lead to a perceived loss of quality even if the printing remains intact.
Contracts for archival materials often prohibit the use of these additives to ensure long term visual stability.
