Products for measuring color can be broken down into those for water and those for the color grading of maple syrup and honey.
Color of Water
Used in natural water based applications, such as drinking water and municipal wastewater treatment, the color of water may dictate the presence of both unwanted inorganic and organic material; removal results in more suitable water for general and industrial applications. Color is measured in Platinum-Cobalt units (PCU). The AWWA recommends ≤ 15 PCU.
True color is caused by both natural or artificial compounds dissolved in water. Apparent color is caused by both dissolved and suspended solids. The term ‘‘true color’’ is defined as the color of water from which turbidity has been removed. The term ‘‘apparent color’’ includes not only color due to substances in solution, but also color that is due to suspended matter.
Apparent color is determined on the original sample without filtration or centrifugation. In some highly-colored industrial wastewaters, color is contributed principally colloidal or suspended material. In such cases, both true color and apparent color should be determined. To determine true color, turbidity must be removed before analysis.
Color Grading of Maple Syrup and Honey
The color grading of maple syrup and honey is simplified by the use of a photometer. The photometers use a light source and the principal of absorbance to determine the color differences between samples. This type of measurement is not subjective to interpretation since a meter with a silicon photocell is determining how much light is passing through the sample. A glycerol standard is used for 100% transmittance that the measurements are then based on.
Hanna Instruments offers several products for measuring the color of water and the grading of maple syrup and honey. Choose our Checker Handheld Colorimeter or one of our portable or bench top photometers for accurate, affordable measurements of color.
Below are the most common products used for measuring color.
Spectrophotometers are available that have the color method and the maple syrup grading method pre-programmed into the meter. There are many other key water quality parameters also built-in to choose from. The spectrophotometer offers the highest precision due to the quality of the optical system that has a wavelength accuracy of +/- 1.5 nm. The spectrophotometer allows for custom methods to be used.
Benchtop photometers include multiparameter versions for water treatment, wastewater treatment, and environmental use. Each photometer is customized to have the parameters used by a specific industry. All benchtop have a digital pH electrode input allowing it to be used as a traditional pH meter.
Portable photometers are available for measuring the color of water and the grading of honey. The portable photometer for color of water has a CAL Check feature that allows for performance verification and, if needed, recalibration using the CAL Check standards. This meter is available as a meter only or as a kit. The kit version includes a rugged carrying case and CAL Check standards.
The Checker HC, like the portable and benchtop instrumentation, use the Beer-Lambert principle to determine the color change. The color change is measured by a photoelectric cell which is more accurate than subjective visual interpretation. Checker HC are available for both the color of water and maple syrup grading.
Solutions for color measurement include the CAL Check standards for verifying and calibrating the portable photometers if necessary. Each CAL Check standard is supplied with a Certificate of Analysis stating the accuracy and traceability of the standard.
Accessories include spare cuvettes and caps for photometers. Cuvette cleaning solution and microfiber cleaning cloths are also available.