SpectrophotometerAfter long-term use or transportation, measurement errors may occur due to light source attenuation, optical path deviation, environmental interference, etc. Regular calibration is required to ensure the accuracy of color measurement data. The following are the general error correction steps and precautions, suitable for most mainstream models of equipment.

1、 Preparation before calibration

Environmental calibration

Place the device on a workbench without direct sunlight or obvious vibration, with an ambient temperature controlled at 23 ± 2 ℃ and a relative humidity of 45%~65%, to avoid temperature and humidity fluctuations affecting the stability of the light path.

Preheat the device for 30 minutes to ensure stable operation of core components such as the light source and detector.

Accessory Inspection

Prepare the original factory standard whiteboard (standard reflector) and blackboard (zero reflector), check that the surface of the whiteboard is free of stains, scratches, aging, and yellowing, and that the blackboard is not damaged; If the accessories are damaged, they need to be replaced in a timely manner, otherwise it will introduce correction errors.

Clean the optical glass measuring the aperture and gently wipe it with a dust-free soft cloth dipped in anhydrous ethanol to remove impurities such as dust and fingerprints.

Parameter Confirmation

Verify the current measurement mode of the device (such as SCI with mirror reflection/SCE without mirror reflection), light source type (D65, A light source, etc.), observation angle (45/0, 0/45, etc.), to ensure consistency with calibration requirements.

2、 Core calibration steps

1. Zero point correction (blackboard correction)

Find the "Zero Point Calibration" or "Blackboard Calibration" option in the device menu and start the calibration program.

Place the blackboard steadily into the measuring port, ensuring complete coverage of the measuring aperture without any light leakage gaps.

Press the "Confirm" button, and the device will automatically collect the reflectance data of the blackboard (theoretical value is 0), completing the zero point benchmark setting.

After calibration is completed, the device will prompt "Zero calibration successful"; If the prompt fails, it is necessary to check whether the blackboard is placed in place and whether the measuring port leaks light, and then operate again.

2. Benchmark calibration (whiteboard calibration)

After zero point calibration is completed, select the "Reference Calibration" or "Whiteboard Calibration" option from the menu.

Remove the blackboard, place it into the measuring port, and gently press it until it fits tightly to avoid measurement deviation caused by the whiteboard tilting.

Press the "confirm" button, and the device will collect standard reflectance data (usually 99%~100%) of the whiteboard as a reference for measurement.

After successful calibration, the device will save the benchmark data; If the surface of the whiteboard is contaminated, it will result in a low calibration value, which needs to be cleaned and recalibrated.

3. Sample calibration (optional, for special errors)

If there is a significant deviation in the data when measuring a specific color sample, a standard color chart can be used for sample calibration:

Select color blocks with known standard values and place them in the measuring port for measurement.

Compare the measured values of the equipment with the standard values on the color chart and calculate the deviation value.

Enter deviation compensation parameters in the "error compensation" function of the device, or perform data calibration through software.

3、 Verification after calibration

Using calibratedSpectrophotometerRepeat the measurement of the standard whiteboard and check if the reflectance value is close to the standard value (a deviation of ≤ 0.5% is considered qualified).

Measure typical color blocks on the standard color card (such as neutral gray, pure red/green/blue), compare the measured values with the calibration values on the color card, and ensure that Δ E (color difference) is ≤ 0.3 to ensure that the calibration effect meets the standard.

If the verification fails, it is necessary to check whether the whiteboard/blackboard is malfunctioning and whether the optical path is offset. If necessary, contact the manufacturer for professional calibration.

4、 Precautions

Calibration cycle: It is recommended to perform zero point+benchmark calibration once a week for daily use; Frequent use or high-precision measurement scenarios require calibration before each use.

Accessory maintenance: Whiteboards should be stored away from light and regularly cleaned with specialized cleaning agents; Do not touch the surface of the whiteboard directly with your hands to prevent contamination.

Avoid interference: During the calibration process, it is forbidden to move devices or block the measuring port, and there should be no strong electromagnetic interference around (such as high-power motors and frequency converters).

Professional calibration: The equipment needs to be sent to a third-party metrology institution or manufacturer for metrological verification every year, and a calibration certificate must be issued to ensure compliance with industry standards.