Tuesday, 18 September 2012

Shiny Surfaces

Exercise  - 4-10 photographs

Depending on the object being photographed the reflected light will have an effect on the final image. Most surfaces reflect light as a combination of diffuse reflection, where the reflected light is scattered equally in all directions and direct reflection, where the reflected light bounces back at exactly the same angle as it is transmitted. It is important not to confuse diffuse transmission of light and diffuse reflection here.

Diffuse transmission - is diffusing the light source by use of a light tent or other translucent material. This has no effect on whether the reflection is diffuse.
Diffuse reflection - is light reflected from a subject.

Diffuse reflections are the same brightness no matter which angle we view them. Because shiny surfaces like polished metal transmit mainly direct reflection it is very difficult to photograph without seeing the light source as a "hot spot" in the metal. In my limited experience of photographing metal not only can you see the light source but also the entire surrounding area reflected in the surface.

For this exercise a shiny object is photographed from above firstly without any special "equipment" and then using some tracing paper in the shape of a cone and some experimentation in lighting angles to see what effect this can have.

This is the recommended "equipment". A shiny object, in this case an ice cream scoop, scissors, sellotape and some tracing paper.

 
 
You can see from the following reference photograph the common problems of shooting shiny objects.
Photographing a shiny object

The next two images show the use of the cobbled together paper cone which sits around both the object and the camera lens and effect of moving the light source.


Light source closer.
I suppose you could say the resulting images are marginally better with the paper cone, at least the reflection of the surroundings, camera and photographer have been removed. Moving the light source had little effect on the reflection nor did rotating the object. I expect the results would have been better if I had been able to get some proper white tracing paper and not had to use an alternative which has resulted in a colour cast on the images, or perhaps used a shiny object with a textured surface.

I can see in theory how this works but the exercise was a bit of a nightmare. Trying to construct the cone and secure it around the lens and also the object being photographed was really fiddly and time consuming. The tracing paper cone idea does result in less extraneous reflections from the surroundings but doesn't completely remove the view of the lens in the final image. I'm now left wondering how a professional would handle photographing this sort of surface and reminded why I try to avoid them.  

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