This module is based on the I2C light-to-digital converter TSL2561.
This module transforms light intensity into a digital signal. This module is different from Grove - Light Sensor, this digital module features a selectable light spectrum range due to its dual light sensitive diodes: infrared and full spectrum.
You can switch between three detection modes to take your readings. They are infrared mode, full spectrum and human visible mode. When running under the human visible mode, this sensor will give you readings just close to your eye feelings.