Effect of Optical Brighteners in Color Measurement

Optical brightening agents (OBAs) are commonly added into many products, from paper and textiles to plastics and detergents, to achieve a brighter and whiter appearance. OBA absorbs energy in the invisible ultraviolet (UV) area (mostly below 400nm) and re-emit that energy in the blue area of the visible spectrum (400-480nm). This resulted in a spike in the reflectance curves at the blue area, making products with OBA perceived as brighter and whiter.

For OBA enhanced products, measuring and maintaining their color consistency can be challenging as the amount of OBA used can influence how color is perceived. Products may appear to have a similar shade of white under one lighting (production floor) but different under another (retail store) due to the varying amounts of OBA used.

Accurate and reliable measurement of OBA enhanced products requires a spectrophotometer that uses calibrated UV light. Conventional spectrophotometers use a mechanical UV filter that decreases the amount of UV energy its lamp emits. This technology requires constant adjustment to the UV filter to compensate for the decreases in UV energy.

Unlike the conventional spectrophotometers, Konica Minolta Spectrophotometer CM-36dG and CM-36dGV uses the patented Numerical UV Control (NUVC) technology that calibrates and controls the UV content with each measurement. It combines the flashes from 2 xenon lamps, one for full UV and another with a 400 or 420nm UV-cutoff filter, using proprietary calculations. With this, the right filtering method can be chosen without mechanical filter positioning or the need to check the calibrated UV content during each measurement. Check out this application note to learn more.

The CM-36dG and CM-36dGV, designed with enhanced useability, comes with innovative features, like the Wavelength Analysis & Adjustment (WAA) function, that caters to today’s measurement needs. Watch this video about CM-36dG to find out more.

Need help evaluating OBA enhanced product? Contact us for a free consultation with our color application specialists.