1. What is Light Meter (RGB & Luminance)?

Light Meter (RGB & Luminance) is a browser add-on that helps you easily measure some important light factors, such as luminance, and RGB (red, green, and blue) values. When you open the app for the first time, it may ask you about camera access. Please accept the dialog box to start the app. Also, note that the app may take a few seconds before be ready. So please be patient while the addon is getting ready. Once the loader is disappeared, the addon is ready to use. It uses the camera in your system to capture the surrounding light. If your computer does not have a camera, please attach one to it before using the addon. On the top toolbar in the interface, you see some information. On the top right side, there is a button to reload the UI, and also there is a button to open the support page. Please read the below FAQ items to get more info about this addon and how it works.

2. How can I work with this add-on?

As mentioned above, simply open the interface, and start using the app. The addon may ask you about the camera access permission. Please accept the permission before using the addon. As mentioned above, the top toolbar contains several important metrics about the surrounding light. From left to right, the first item is the light component (RGB) values. Next, is the luminance value based on the light parameters. The total duration that the current light is being monitored is the next item. There is also a calibration field that you can use to adjust the light level if it is not accurate on your machine. Once you change the calibration value, please press the reload button for changes to take effect. The last button is for showing the camera within the app interface. At the bottom, you can see a precision range controller to adjust the input criteria. By default, the app only monitors a (16 x 16) pixel area from the camera to measure the light. You can decrease or increase this value. When the pixel area is increased, the overall precision becomes more accurate as values are captured and measured from more pixels. Currently, the maximum pixel area is (128 x 128) pixels.

3. How can I download the source code for Light Meter (RGB & Luminance)?

To download the source code for this extension from Chrome Web Store, it is recommended to use Extension Source Downloader. With this addon, you can download the source code as a ZIP or CRX format to your machine. If you want to download the source code from the Firefox addons store, please open the firefox download link (if available) in the Firefox browser and then right-click on the - Add to Firefox - button and select - Save Link As... - item. Choose the destination folder on your machine and then save the file in XPI format. You can then rename the XPI format to a RAR or ZIP file. Some extensions may have a GitHub repo address, which you can use to download the source code as well. But, it may not be the latest version of the addon. Therefore, downloading the source code from the official web stores is the best option as it always gives you the latest version of the addon.

4. What is the RGB value in light measurement?

RGB stands for Red, Green, and Blue. In color theory, these are primary colors that can be combined in various ways to create a wide range of hues. In digital imaging and computer graphics, the RGB color model is used to represent and display images, with each pixel represented by a combination of red, green, and blue values. These values typically range from 0 to 255, with 0 indicating the absence of that color and 255 indicating the highest intensity of that color.

5. What is Luminance in light mesurement?

Luminance is a measure of the amount of light that is emitted or reflected by a surface and is often used to describe the brightness of a display or image. The human eye is more sensitive to some colors than others, so the luminance of color is not the same as its perceived brightness. There are several ways to convert RGB values to luminance, depending on the specific application. One common method (also used in this app) is to use this formula: 0.2126 * R + 0.7152 * G + 0.0722 * B. It is based on the CIE 1931 color space and the human visual system sensitivity to different colors. The coefficients (0.2126, 0.7152, and 0.0722) are the weights assigned to each color channel (red, green, and blue) that represent the luminous efficiency of the human eye for each channel. This formula is often used when working with digital images.

6. How does the Light Meter add-on work?

This addon uses a JavaScript Canvas API to capture and calculate light factors. This API is included in all modern browsers (Chrome, Edge, and Opera). Moreover, for displaying data as a chart, this addon is using a free and open-source library called Chart.js. As mentioned above, to measure the light, this app uses the camera on your system. So please make sure the browser has camera permission before using this app.

7. What does calibration value mean?

Calibration value is a factor to adjust the light level. Normally it should be zero, but depending on your system or camera type, you might need to add a calibration value in order to adjust the light level. The default value for calibration is 0.

8. How do I turn the extension OFF?

When app UI is closed, this addon is completely OFF and has no usage (RAM/CPU) at all. Alternatively, if you want to completely turn off the addon, please head to the extensions tab in your browser and then click on the disable button from there.

9. How can I reload the app UI?

When you open the app UI, you will see a reload button on the top toolbar (1st button from right). Please press on this button to reload the UI. Also note that, reloading the UI will terminate the monitoring process and resets the camera usage.

10. How is the performance of this addon?

The performance of this addon is comparable to the actual devices for light measurement. Moreover, it is very similar to light meter apps for mobile devices (android or iOS). Therefore, use this addon where ever you have your computer with you. You can make adjustments to the light level with the calibration value. Please note that some cameras may have auto-focus or auto-exposure features that may degrade the accuracy of this addon. So please try to turn off this feature if you want a precise measurement with the computer camera.

11. Where can I find the privacy policy for Light Meter (RGB & Luminance)?

Please read the privacy policy for this extension here.