Online full-spectrum color analysis with the Valmet IQ Web Color Measurement (IQ Web Color) provides reliable data for Valmet’s unique, multi-variable MD color control.
The Valmet IQ Web Color is an advanced spectrophotometer suitable for a variety of paper and board grades where visual uniformity is a key quality. Newsprint, printing papers, fine papers, covers and packaging materials benefit from the full-spectrum color measurements of the Valmet IQ Web Color.
Capable of detecting detailed effects of furnish, dyes and optical brightening agents, the Valmet IQ Web Color measures sheet color, brightness, whiteness and opacity. The sensor provides opacity compensated color measurements for both UV-included and UV-excluded color.
In the detector head, the light source is a flashing, UV-rich Xenon lamp, followed by a filter wheel to provide the illumination for UV-included and UV-excluded color measurements. The light reflected from the sheet is detected by the 1st channel of the dual spectrophotometer. Simultaneously, the illumination spectrum is detected by the 2nd channel which is used to compensate for environmental variations.
On the opposite side of the web, a white LED is used as an illumination of the transmission spectrum that is detected in the detector head. Single sheet color measurements are corrected to infinite backing values using an advanced proprietary algorithm.
The simple, compact design of the dual spectrophotometer ensures that optical alignment and measurement stability are maintained. With illumination from all directions, color and brightness measurements are independent of sheet surface properties such as fiber orientation.