Precision Test Report on Color Temperature and Illuminance of the Gravity CCT & ALS Meter

Accurate measurement of color temperature and illuminance is crucial for image quality, especially in photography and videography. This article delves into the physical significance of color temperature and illuminance, their importance across various applications, and evaluates the measurement precision of the Gravity: Factory Calibrated Correlated Color Temperature (CCT) & ALS Meter under different environments. You will gain insights into the accuracy of this sensor's measurements and understand the contexts in which it excels.

Part 1: Introduction to Color Temperature and Illuminance

1. What are Color Temperature and Illuminance?

• Color Temperature: Measured in Kelvin (K), it represents the hue of the light emitted by a source, ranging from warm reds to cool blues. Accurate color temperature measurement is highly important in photography.
• Illuminance: Measured in lux, it quantifies the amount of light falling on a surface, impacting the brightness and visibility of a scene.

2. Why is Measuring Color Temperature and Illuminance Important?

• Color Temperature: Various lighting conditions, whether natural or artificial, can alter the colors in an image, potentially leading to unrealistic or undesirable results. For instance, a warm light source may cast a yellowish tone, while a cool light source might produce a bluish tone. Professional tools are essential to measure and adjust color temperature in high-quality photography and post-production work to ensure that the captured images reflect true colors.
• Illuminance: It affects exposure and clarity during photography. Accurate illuminance measurement allows photographers to adjust camera settings for optimal exposure, helping to avoid overexposed highlights or underexposed shadows.

Beyond the imaging industry, measuring color temperature and illuminance also plays a role in creating visually appealing and comfortable spaces in interior design. In health and wellness, these measurements help optimize lighting conditions to improve sleep, mood, and productivity.

Part 2: Product Introduction

The Gravity: Factory Calibrated Correlated Color Temperature (CCT) & ALS Meter is a high-performance optical sensor device designed to meet the needs of professional videographers and photographers. It can accurately measure correlated color temperature and illuminance intensity. Its illuminance measurement range is 10-10,000 lux, with an error margin of ±5 lux + ±10% lux, and the correlated color temperature measurement range is 2700-6500K, with an error margin of ±10% K, ensuring perfect lighting for any environment.

Part 3: Test Data

In this section, we present and analyze the test data of the Gravity: Factory Calibrated Correlated Color Temperature (CCT) & ALS Meter.

Test Equipment: 

CL-200A Color Illuminance Meter: The CL-200A is a high-precision optical measurement instrument manufactured by Konica Minolta, Japan, widely used for color and brightness measurements of various light sources. In this test, the CL-200A serves as a reference device, and its high precision and stability make it an ideal benchmark for evaluating new optical measurement devices like the Gravity CCT & ALS Meter. By comparing the data from the Gravity CCT & ALS Meter with the CL-200A, you can intuitively assess the performance of the device.

Standard Light Boxes (D65, TL84, F): Color-matching light boxes are commonly used for color detection, ensuring precise data acquisition when assessing color deviations under different lighting conditions. D65, TL84, and F are standard light sources, simulating various environmental light conditions. Therefore, we selected these standard light boxes to provide a comprehensive and reliable performance evaluation of the Gravity CCT & ALS Meter's color measurement accuracy.

Test Environment 1: Standard Light Source D65

D65: A simulated daylight artificial light source with a spectrum that meets the visual color standards of European and Pacific Rim countries. The "D" in D65 stands for "day," and D65 refers to the color at a color temperature of 6500K.

Conclusion: Under the D65 light box environment:

• Lux illuminance: The error is within ±7.02%, demonstrating good stability and precision.
• CCT color temperature: The error is within ±1.8%, showing high accuracy in color temperature measurement.

Both color temperature and illuminance errors are within 7%, making it suitable for use in standard light source environments.

Test Environment 2: Standard Light Source TL84

TL84: A narrow-band fluorescent light source, classified as a tri-phosphor fluorescent lamp. It is widely used in retail and commercial environments, such as supermarkets and malls. TL84 is a common store lighting source in European and Asian markets, so color matching and product display in these environments need to be calibrated and tested based on the TL84 light source. Its color temperature is approximately 4000K, conforming to the CIE Standard Illuminant F11.

Conclusion:

• Lux illuminance: The error is within ±6.34%, showing slight fluctuations, but overall, the error is controlled within an acceptable range.
• CCT color temperature: The error is within ±5.35%, demonstrating good consistency in color temperature measurement.

In the TL84 environment, both illuminance and color temperature errors are within 6%, making it suitable for use in simulated indoor lighting environments.

Test Environment 3: Light Box F

Light Box F: Contains various fluorescent light sources typically used to simulate artificial lighting conditions in homes and commercial environments. The F series lamps cover a wide range of color temperatures, from cool white to warm white, making them standard light sources for testing color performance under home lighting conditions.

Conclusion:

The Lux illuminance error is within ±5.92%, indicating relatively stable illuminance measurement. The CCT color temperature error is within ±2.08%, demonstrating very precise color temperature measurement. In the lightbox F environment, the sensor's color temperature and illuminance errors are both within 6%, making it suitable for use in environments with standard fluorescent lighting.

Test Environment 4: Indoor Natural Light

Reason for Testing: The primary reason for testing in a natural light environment is to verify the accuracy of the Gravity CCT & ALS Meter in real-life applications. Natural light is one of the most common light sources and is considered one of the ideal light sources in photography and videography.

Environment Description: In this test, an indoor environment with ample natural light was selected. The test was conducted in a well-lit office where natural light from outside is evenly distributed across the testing area through windows. No artificial light sources were present to ensure the purity and uniformity of the natural light.

The indoor natural light environment simulated typical daily lighting conditions, making the test more relevant to the actual usage scenarios of users. Sunlight entered the room through the windows, providing soft and diffused light, thus avoiding the impact of strong direct light on the test results. Such an environment effectively assesses the accuracy of CCT & ALS Meter's color temperature and illuminance measurements under natural light, especially when no artificial light sources interfere, providing a more realistic reflection of the device's performance in natural light.

Conclusion: In an indoor natural light environment, the Lux illuminance error is within ±16.61%, which is relatively large due to the influence of environmental light changes. The CCT color temperature error is within ±5.48%, indicating relatively stable color temperature measurement. The significant illuminance error suggests that it may not be suitable for high-precision lighting measurements, but the color temperature measurement remains valuable.

Test Environment 5: Indoor Lighting

The test device was placed on a desk, surrounded by typical indoor lighting conditions. The room had several windows, and although curtains partially blocked the natural light, the indoor lighting was still sufficient and uniform. This environment simulated the lighting conditions in most indoor scenarios, with light primarily coming from overhead artificial lighting and a small amount of natural light filtering through the curtains.

Such an environment is suitable for testing the device's performance in everyday indoor work environments, ensuring that accurate color temperature and illuminance measurements can still be achieved under artificial lighting, thus meeting color management needs in indoor lighting conditions.

Conclusion: In an indoor lighting environment, the Lux illuminance error is within ±5.53%, indicating high precision in illuminance measurement. The CCT color temperature error is within ±4.92%, demonstrating accurate color temperature measurement. With both color temperature and illuminance errors within 6%, the device is suitable for general indoor lighting measurements.

Test Environment 6: Bright Natural Light

This test was conducted outdoors, with the device placed in an open space fully exposed to bright natural light. The purpose of this scenario was to evaluate the measurement accuracy and stability of the device under direct sunlight or intense natural light conditions. Since outdoor lighting can vary significantly, testing under bright natural light ensures that the device can still provide accurate color temperature and illuminance measurements under different lighting intensities and conditions. This is particularly crucial for scenarios where consistent color performance is required under varying light conditions.

Conclusion: In a bright natural light environment, the Lux illuminance error is within ±11.8%, showing a relatively large error in high-brightness conditions. The CCT color temperature error is within ±3.68%, indicating good color temperature measurement performance. Although the illuminance measurement error is significant, the color temperature measurement is precise, making the device suitable for applications with high color temperature requirements.

Test Environment 7: Low Light Environment 1

This test environment is characterized by controlled low-light conditions, where ambient light intensity is extremely low. The main objective is to measure light intensity and color temperature in dim lighting conditions. The light is intentionally dimmed to simulate scenarios such as nighttime indoors or low-brightness environments. This test environment is particularly important for evaluating the device's ability to detect small changes in light intensity and color temperature under low-light conditions, which is crucial for applications like nighttime photography or dim indoor lighting.

Test Environment 8: Low Light Environment 2

In this test environment, the light is further reduced, with almost no natural or artificial light sources present. The device is placed on a carpet, focusing on assessing the meter's performance on different surfaces and under low-light conditions. The light is dimmed to simulate extremely low-light environments, such as a theater or nighttime events. Testing in such an environment helps verify the device's accuracy in detecting and responding to slight changes in light, which is critical for environments requiring precise light control.

Test Environment 9: Low Light Environment 3

In this final test environment, light is reduced to almost complete darkness, simulating conditions close to total darkness. The test aims to detect the sensor's limit in detecting light. The focus is on whether the device can effectively function in conditions where the human eye can barely perceive light, which is particularly relevant for applications in security, astronomy, or specialized photography.

Conclusion:

The sensor shows significant errors in illuminance measurement under low-light conditions, making it unsuitable for low-brightness measurement applications.

The Gravity CCT & ALS Meter performs well in most standard light sources and indoor lighting environments, especially in color temperature measurements where the error is relatively small. However, there are significant errors in illuminance measurements in both high-brightness and low-light environments, so it is recommended to use caution in applications requiring high-precision measurements.

Part 4: Product Use Cases

Based on the test data, here is an analysis of the suitable use cases for the Gravity CCT & ALS Meter:

Indoor Lighting Systems

Performance Data:

• Lightbox F Environment: Lux error within ±5.92%, CCT error within ±2.08%.
• Indoor Lighting Environment: Lux error within ±5.53%, CCT error within ±4.92%.

Analysis: The Gravity CCT & ALS Meter demonstrates high accuracy in both simulated indoor lighting environments (like Lightbox F) and actual indoor lighting environments, with Lux errors within 6% and CCT errors within 5%. Therefore, this device is well-suited for designing and tuning indoor lighting systems, ensuring that the brightness and color temperature of lights meet set requirements and provide a comfortable indoor lighting environment.

Credit: lighting-singapore.com

Exhibition Hall Lighting Systems

Performance Data:

• Lightbox TL84 Environment: Lux error within ±6.34%, CCT error within ±5.35%.
• Lightbox D65 Environment: Lux error within ±7.02%, CCT error within ±1.8%.

Analysis: Exhibition hall lighting systems require precise light source control to highlight the colors and details of exhibits. The Gravity CCT & ALS Meter performs well in the TL84 and D65 lightbox environments, especially in color temperature measurements where errors are minimal. Therefore, this device can help ensure the stability of light source color temperature in exhibition halls, enhancing the visual appeal and attractiveness of exhibits.

Credit: itourcard.com

Lighting Quality Testing Equipment

Performance Data: Test Data in Various Environments: Lux error ranges from ±0.39% to ±16.61%, CCT error ranges from ±0.11% to ±7.17%.

Analysis: As lighting quality testing equipment, the Gravity CCT & ALS Meter performs differently across various light source environments. For scenarios requiring strict quality control, such as lighting manufacturing or quality testing, the device excels in standard lightbox environments (such as D65 and TL84), and can be used to check whether the color temperature and brightness of lights meet the standards.

Credit: aqiservice.com

Supermarket Lighting Systems

Performance Data:

• Lightbox F Environment: Lux error within ±5.92%, CCT error within ±2.08%.
• Indoor Natural Light Environment: Lux error within ±16.61%, CCT error within ±5.48%.

Analysis: Supermarket lighting systems need to balance the brightness and color temperature of light to attract customers and showcase products. The Gravity CCT & ALS Meter performs well in the Lightbox F environment, helping design suitable lighting schemes. Additionally, the device shows minimal error in color temperature measurement in simulated indoor natural light environments, making it suitable for real-time adjustments in the variable lighting conditions of supermarkets.

Credit: jylrfid.com

Screen Display Adjustment

Performance Data:

• Indoor Lighting Environment: Lux error within ±5.53%, CCT error within ±4.92%.
• Bright Natural Light Environment: Lux error within ±11.8%, CCT error within ±3.68%.

Analysis: Screen display adjustment requires a quick and precise response to changes in ambient light to ensure the stability of the visual experience. The Gravity CCT & ALS Meter performs well in indoor lighting environments, making it suitable for automatic adjustment of screen brightness and color temperature in general indoor settings. Additionally, the device maintains good accuracy in color temperature measurements even in bright natural light environments, making it suitable for real-time adjustments in environments with changing light conditions to maintain display quality.

Credit: windowslatest.com

Summary

Through this test, we conducted an in-depth evaluation of the Gravity: Factory Calibrated Correlated Color Temperature (CCT) & ALS Meter's performance in measuring color temperature and illuminance across various environments. The results demonstrate that the device exhibits excellent accuracy in both color temperature and illuminance measurements under standard light sources such as D65, TL84, and F-type light boxes, with measurement errors well within acceptable ranges. This makes it suitable for high-precision applications such as professional photography and videography.

In environments with indoor natural light and typical indoor lighting conditions, the device continues to display stable performance in color temperature measurements. Overall, the Gravity CCT & ALS Meter consistently delivers reliable color temperature and illuminance data across different lighting conditions, making it particularly suitable for color management and illuminance assessment under controlled lighting environments. For professional scenarios requiring precise light measurement, it remains a dependable tool.