RAL Effect RAL 170-4

Light Reflectance Value measures the amount of visible and usable light that reflects from a painted surface.
Simply put, the higher the LRV of a paint color, the brighter the room you will get.
The scale goes from 0% (absolute black, absorbing all light) to 100% (pure white, reflecting all light).

Act like a pro: When choosing paint with an LRV of 69.3%, pay attention to your bulbs' brightness. Light brightness is measured in lumens. The lower the paint's LRV, the higher lumen level you need. Every square foot of room needs at least 40 lumens. That means for a 200 ft² living room you'll need about 8000 lumens of light – e.g., eight 1000 lm bulbs.