The Direction property of light is as important as any of the other properties of light. I choose to discuss it last as it interacts with all the other properties. Light direction can enhance or subdue texture, form and space. The results of light direction become the visual impact of a photo much more than any of the other properties of light.
Diffuse light sources tend to hide the direction of light while specular light brings out the direction. Light direction also affects surface quality. Think of a rough surface like a patch of dirt and shine a specular light on the surface at an angle so it bounces right back at your eye. The diffuse surface now becomes specular and the color is desaturated all from the direction of the light source. If a light is off to the side and skims across a surface it will appear less bright than if the light struck the surface more directly. With the skimming light texture of the surface will become prominent which is why the light will appear to be less bright. When a light comes from behind it skips off the edges the color of the edges are desaturated and light appears to be much brighter than if it came from the front or side.
There are myths associated with the direction of light. Keep the sun over your shoulder is safe but boring. This type of light lacks texture shape and form. On camera flash is the same unless it is used for fill. Another myth is the you can’t get a good picture at noontime. Nobody told this to Edward Weston and he did a noontime shoot on a beach with the models lying in the sand. I got to hold and closely examine a set of these images and I must say they were some of the finest I have ever seen. The skin was alive with shape and texture as Edward had taken advantage of the direction of light.
There is one rule when it comes to the direction of light. The angle of incidence is equal to the angle of reflection. If a light hits a surface at 30 degrees it bounces off at 30 degrees. In the studio when light placement become difficult this rule can be applied. Replace the camera with a light then walk around the product to find locations for you lights to yield the best results. What you see is what you will get. I used this on chrome shooting often and on automotive shoots when needed. It made for fast and accurate light placement.
Control of the direction of light is easy in the studio just move the light. Outdoors it is hard to move the sun so we must move the subject or our camera angle. Sometimes you may need to return at a particular time of day. Luckily today we have apps that will tell us where the sun will be at any time of the day and the moon at night. When I am walking and hunting for an image to capture I alway look in all directions as the light changes when I change direction. Once I find a subject I explore that subject looking at different angles for light and composition.
Well that does it for the direction of light and the four properties of light. What’s next I don’t know but I do have a lot of ideas so I hope you subscribe and continue to enjoy. Until next time “Keep on Shooting”