Haze measurement can be distorted by scratches on the surface, dust, temperature, and light. 

Since part of the light will pass through the light-transmitting materials, the colorimeter is not suitable for color measurement of such kinds of materials; however, when place a pure color material with uniform texture under the light-transmitting material, we can measure the color difference between the standard and the sample. 

Techniques of measuring color are visual color comparison, colorimetry (with colorimeters) and spectrophotometry (measuring spectral reflectance), and image analysis. Both techniques measure the reflection or absorption of light by materials and are commonly quantified. Therefore standardized in color spaces such as CIELAB or RGB.

Take L*a*b* readings of two samples using a colorimeter or spectrophotometer and calculate color difference using the 3 formula (Delta E). The difference in 0 is the reported Delta-E, which shows how visible the change is, whereas the thresholds define the acceptability as per the application requirements.

A Spectrophotometer color measuring device objectively determines the color of a surface. It is used wherever accurate color matching, reproducibility or deviation control is needed – for example in quality assurance, product development or incoming goods inspection.

Spectrophotometer color measuring devices primarily perform three key tasks:

Capture color information: They detect light reflected, transmitted, or emitted by a sample using optical sensors.
Quantify color data: They convert the captured optical signals into standardized numerical values, such as RGB, CMYK, or CIELAB coordinates.
Compare color consistency: They compare the measured color data of a sample against a target or standard to assess color accuracy and uniformity.

 A gloss meter measures the amount of light reflected from a surface at a specific angle. It's commonly used to assess surface finishes such as paint, coatings, plastics, and paper for consistency, quality control, and visual appearance evaluation.

Plastics, glasses, films, coatings, and packaging materials are common uses of hazemeter to monitor consistency and quality. 

In the study of chemical reactions, calorimetry deals with changes in heat (energy and enthalpy). Spectrophotometry is the measurement of the light absorbance or light transmittance to determine the concentration or color of a solution. The first one monitors the thermal processes, whereas the second one addresses the aspects of light and color.

Zero calibration of a hazemeter is a critical pre-measurement procedure to ensure the instrument’s accuracy by resetting its baseline to "zero" when no haze or light attenuation is present.

1. Align the hazemeter’s measurement window with air or a black background, ensuring no objects block the window.

2. Press the hazemeter’s zero calibration button and wait for the instrument to complete automatic calibration. At this point, the instrument should display a zero haze value and a zero light transmittance value.

3. Observe the instrument’s display to confirm the zero calibration result stabilizes near zero. If the zero calibration is inaccurate, repeat the above steps multiple times until the displayed haze and light transmittance values stabilize near zero.

Perform 0-degree calibration before testing, this eliminates inherent instrument drift, environmental interference, or residual signal errors, ensuring subsequent measurements of transparent/translucent samples (e.g., plastic films，pvc, glass, coating, displays and cosmetic packaging) are reliable. Correct for minor instrument deviations caused by long-term use, temperature changes, or power fluctuations.

A coating thickness gauge measures coating thickness. It measures coating thickness using three different principles: magnetic induction, eddy current, or ultrasonic. Depending on the coating type and the coating's substrate material, the appropriate principle is selected. For industrial and laboratory use, most of these units deliver accurate, non-invasive readings.