The model AF26 is a dual channel absorption sensor designed for inline applications. It accurately measures color or color changes and can be used in a variety of industrial processes, from sanitary CIP/SIP applications to high-pressure, high-temperature industrial applications. The AF26 sensor uses light in a range from 385 to 1000 nm at selected wavelengths. A precisely defined, constant light beam penetrates the process medium. The light beam is divided into two beams and passes through two specific interference filters at the application-dependent wavelengths. The attenuation of the light intensity, caused by absorption and/or scattering of the dissolved and undissolved substances, is detected by two hermetically-sealed silicon photo diodes. This dual channel absorption technology compensates for turbidity in the process stream and even the smallest presence of color can be measured.