Abstract: A meter for measuring the turbidity of a fluid includes a light source for directing a light beam through a fluid under test towards a reflective surface and a sensor for detecting light reflected from the reflective surface and passing back through the fluid under test. The meter outputs a signal indicative of the turbidity of the fluid under test.

Abstract: A counterfeit ink detector comprises a color printer calibrated by determining authentic ink color values for several authentic inks used by the color printer. A multi-color pattern is printed using multi-colored inks of a print cartridge. A light source outputs light to the color pattern and a color sensor detects light from the light source reflected from the color pattern. A processor processes the detected light to calculate pattern color values for color components of the color pattern, and compares the pattern color values to the authentic ink color values. A counterfeit ink signal is output by the processor if the difference between the pattern color values and the authentic ink color values is greater than a threshold value indicating counterfeit ink.