Light is photography, light is life. It’s light that reveals and hides objects, it can create shadows and depth, or make them disappear and flatten objects. Light is the key to creating vibrant images; so knowing how light changes in intensity and quality very quickly, as well as reflective values of object is one of the hardest things to master.
Light can be hard and directional producing well-defined shadows, or it can be soft and diffused producing softer shadows; each will give you a different effect or mood in your photograph.
Hard light for example isn’t very becoming for flesh, it tends to create shadows from wrinkles and pores. Back lighting an object can accentuate colors and can also be utilized for creating silhouettes and halos. Side lighting can emphasize textures through shadows, and front lighting flattens a photo.