If you'd like to know more about the essential role that light plays in photography, then you’ll love our course, A Photographer's Guide to Light. Much of photography is about managing reflections, and in this lesson you’ll learn about diffuse reflections.
A Photographer's Guide to Light: Diffuse Reflection
There are three types of reflections: diffuse reflection, direct reflection and glare. Most surfaces exhibit a combination of these three and it's the mix of these types of reflection that gives a surface its unique look.
Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than just one angle, as in the case of specular reflection. Essentially, this means that the light will reflect off the surface in many directions.
Diffuse Reflection Example
This is a green laser bouncing off a highly reflective object (part of a hard drive), with some smoke in the air to help you see it better. You can see that the beam of light has a very predictable path.
If the polished metal is replaced with a piece of white paper, you can see that as it hits the paper, there’s no predictable path like there was before. It's being reflected in all directions, including towards the camera, which is what’s making the lens flare that you can see. That’s what diffuse reflections look like. White objects have a lot of diffuse reflection, which is why they look white from any angle you view them from.
Diffuse Reflection in Practice
In the series of shots above you can see a piece of plain white paper on a black tablecloth which has then been photographed from a number of different angles without moving the light source.
You can see the paper looks nearly the same in all of the photos, it doesn't really matter what angle or direction the paper is photographed from, it looks white from all angles. This is because white objects have a lot of diffuse reflection; the light is being reflected towards the camera no matter where it’s shot from.
Diffuse objects are also not really affected by the size or the contrast of the light.
Changing the Light Source
In the two shots above, the bottom one was created with a relatively large lighting source in relation to the objects - a low contrast light. The top image was made with a high contrast light – a smaller source relative to the objects.
You can see that although the shadows and the highlights on the objects change, the white paper look the same in both photographs. Diffuse reflections are not really affected by the size of the light and to some degree, the direction of the light. They are however, affected by the distance of the light, and that’s something we’ll look at in another lesson.
More Resources on Light
About the Authors
David Bode created the video course that includes this lesson. Dave is an expert on video and audio production, and he lives in the upstate NY area. He works as a camera operator, editor, inventor, motion graphics designer, recording engineer, and studio musician.
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