A1: How does a colorimeter work?
Q1: Colorimeters rely on the concept of the Beer-Lambert law, which assumes that the absorbance of a substance is proportional to its concentration. For example, the higher the concentration of a solution, the higher the absorbance reading. Many chemical and biological experiments are based on this concept. To obtain a Beer's law curve, several standards (solutions of known concentration) are prepared and their absorbance values are determined using a colorimeter.
A2: What is colorimetry?
Q2: A colorimeter is a device that measures light absorbance (how much light is absorbed) and light transmission (how much light passes through) in a liquid by analyzing the intensity of the color.
A3: What are the limitations of a colorimeter?
Q3: One limitation of chemical colorimeters is that differences in certain substances may lead to inaccurate test results. According to Global Water Instrumentation, because these differences are different for each substance, a chemical colorimeter alone is not a completely foolproof testing device.
Tips: How does the portable colorimeter detect the color of a pill coating?
A conventional colorimeter is a visual system that simulates the human eye. Using the simulated integral optical system inside the instrument, the tri-stimulus values X, Y, and Z of the sample are integrated and measured, and then parameters such as the chromaticity coordinates of the sample are calculated. The color measurement accuracy of this colorimeter is relatively low. Some products cannot even give the absolute value of the color coordinate space (L, a, b values). Since there is no absolute value data of color, it is impossible to exchange data with others. You cannot create and manage your own color standard database.
A portable colorimeter uses the principle of spectrophotometry to compare the light energy reflected (transmitted) by the sample with the light energy reflected (transmitted) by the standard under the same conditions to obtain the spectral reflectance of the sample at each wavelength, and then uses the standard observer and standard light source provided by CIE to calculate the trimodal values X, Y, and Z according to the following formula, and then calculates them according to the CIEYxy, CIELab, and other formulas to calculate the degree coordinates x. y, CIELAB color parameters, etc. The measured color difference results are more accurate, and a color standard database can be established. However, the surface of the drug is irregular and the surface is not flat. Therefore, when choosing a spectrophotometer, we also need to pay attention to different measurement and observation methods.
The 0/45 degree can only be used to measure smooth surfaces and cannot be used for computer color matching. d/8 degree integrating sphere can be used to measure various surfaces and can be used for computer color matching. Also, consider whether you want to eliminate specular reflections and the measurement modes that include specular reflections when making your selection. If both modes are available, it is useful for measuring smooth surfaces where its color can clearly reflect the surface.