What is reflectance and how does it affect the appearance of objects under different lighting conditions?

Reflectance is the measure of how much light is reflected off an object's surface. It affects the appearance of objects under different lighting conditions by determining how much light is absorbed or reflected, which can change the object's color, brightness, and overall visibility. Objects with high reflectance appear brighter and more vivid, while those with low reflectance may appear darker or less distinct.