Definition
The Rovipen colorimeter is a visual color comparison instrument used to measure the color of liquid or transparent solid samples. It visually matches the color of the sample with a standard color-coded glass piece, thereby quantitatively describing the color characteristics of the sample. The instrument plays an important role in the quality control and standardization process in several industrial fields, and its design is based on colorimetric principles proven by long-term practice.
Principle
The core working principle of the Rovipen colorimeter is visual color matching. A standard light source is provided inside the instrument to provide stable illumination conditions for the observation chamber. The observer simultaneously observes the sample through the eyepiece with an optical window consisting of a standard stained glass filter (usually red, yellow, and blue primary and neutral colors). The combined thickness of each color filter is manually adjusted (expressed in Lo Weipeng units) until the color of the combined color sheet is best matched in the field of view with the color of the sample to be tested. The thickness reading of each filter is the Rovipen value of the sample color. The principle of color superposition can be roughly described by a linear combination: the perceived color of the sample ≈ Σ (standard chromaticity value of the chromatic value × thickness).
Measurement method
Standard measurement processes typically follow relevant industry standards. First, the sample to be tested is injected into a cuvette with a defined light path. Turn on the instrument light source so that the light penetrates evenly through the sample and filter combination. The observer adjusts the knobs for the red, yellow, and blue filters in turn, adding neutral sheets if necessary to adjust the brightness. During the adjustment process, it is necessary to ensure that the two parts of the field of view are completely integrated without dividing lines. The Luo Vipeng unit values for each color filter at the time of matching are recorded, usually reported in the order of red, yellow, and blue. For dark samples, a shorter-path cuvette or the introduction of a neutral filter may be required. The instrument should be calibrated before each measurement and ensure that the observer's visual function is normal and that ambient light interference is minimal.
Influencing factors
The accuracy and repeatability of measurement results are affected by a variety of factors. Instrument factors include the stability and color temperature of the light source, the standardization of the filter, and the aging that may occur with long-term use. Sample factors include uniformity, transparency, and the presence of suspended particles. Operational factors are crucial, such as the observer's ability to distinguish colors, visual fatigue, and consistency of operating specifications. Environmental factors such as stray light from the surrounding environment can also introduce bias. In addition, the cleanliness and matching accuracy of the cuvette's optical path, as well as the fineness of the filter combination adjustment, can affect the final reading.
Applications
Luo Weipeng colorimeters are widely used in industries that require standardized control of product color. In the edible oils and oils industry, it is used to determine the color grades of vegetable oils, animal fats and refined oils. In the sugar industry, it is used to evaluate the color value of sugar liquids, syrups and finished sugars. In the beverage industry, such as beer, juice, etc., it is used to monitor its color consistency. In addition, it is also often used in the chemical field, such as the color evaluation of resins, solvents and certain chemical reagents. It provides an intuitive and versatile means of color quantification for production process control, product quality grading, and trade specification determination in these industries.
Instrument selection considerations
When choosing a Rovipen colorimeter, it needs to be evaluated according to the specific application needs. The first consideration is the measurement range, i.e. whether the combination of filters equipped with the instrument can cover the possible chromaticity range of the sample to be tested. Observing the design of the field of view, such as whether to use a dual or single field of view, will affect the difficulty of matching. The type of light source and its compliance with the relevant standards are the basis for guaranteeing comparability of results. The construction quality of the instrument, such as the durability of the mechanical components and the precision of the filter holder, is related to the reliability of long-term use. In addition, consider whether it is necessary to be equipped with special cuvettes, calibration standards, and models that meet specific industry standards (e.g., AOCS, ISO, etc.). The ergonomic design of the operation, such as eyepiece comfort and knob feel, also has an impact on the convenience of daily use.