Photographing Metal & Reflective Surfaces
Steven Benson is an associate professor and program manager at the Southeast Center for Photographic Studies, which is a consortium between Daytona State College’s School of Photography, the Southeast Museum of Photography and the University of Central Florida’s School of Visual Art and Design.
We asked Steven to provide us an example of a studio assignment that he gives to his students and examples of their assignment work. Here’s how he teaches his students to photograph metal and reflective surfaces:
The purpose of this assignment is to introduce students to the problem solving involved in photographing metallic or reflective subjects.
The goal is to produce two exceptional photographs:
- Shot 1: Photograph of an object with a flat metallic surface.
- Shot 2: Photograph of an object with a curved metallic surface.
As with the glass assignment, the second law of light is important to keep in mind: The angle of incidence is equal to, and the opposite of, the angle of reflectance. This will help you determine where to place the bounce cards.
It’s most important to keep in mind that when photographing metallic objects you are actually photographing what is reflecting off of the objects surface. This principle can easily be seen by placing some loose change on a table. Hold a white piece of paper behind the coins and perpendicular to the surface the coins are sitting on. As you take the paper away from this position and return it you will notice the reflection off of the coins shift from darker (the paper moved away) to brighter (the paper held behind the coins). If you place a black card in this position the coins will reflect black, a red card will reflect red, etc.
The light reflected into a metallic object is best controlled with bounce cards as opposed to direct light from a soft-box, as seen in Figure A, because the cards can be tilted to reduce the brightness level of the reflections.
Image #1 is reflecting the darkness of the studio without a white bounce card:
Image #2 has a white bounce card reflecting into the surface:
Image #3 has the bounce card tilted to reduce its brightness:
If the goal is to have a gradated reflection, then it is necessary to have a gradation on whatever is reflecting into the object (Image #4):
Flat Metallic Surface
When working with a flat metallic object the brightness of the card’s reflection can also be controlled by moving a large bounce card closer or further from your light source. Note: This technique will not work with a curved reflective surface because the change in distance will result in a drastic change to the scale of the reflections.
As with the Second Law of Light, the Third Law of Light (The Inverse Square Law) can also be useful when making decisions about bounce card placement. As it relates to photography, the Inverse Square Law states that the intensity of light is inversely proportional to the square of the distance from the source of that physical quantity (light). What this tells us is that if you double the distance of the card from the light source, there will be a loss of 75% of light, or two stops less light. If you move the bounce card 25% closer to a light source, it will be one stop brighter.
Curved Metallic Surface
A flat surface is easier to photograph because the light reflecting from the surface will only need to come from one direction. When photographing a curved surface, the light reflected back toward the camera must come from a wide arc of illumination, as seen in Figure B.
Image #5 was shot with no bounce cards, while Image #6 was shot with bounce cards).
Objects with curved reflective surfaces are often best photographed in a “tent” enclosure to help surround the subject with a more continuous source of reflection than bounce cards could provide. In Figure C the object was placed inside the “tent” and is lit from the outside. The character of the reflection can be greatly modified by the quality of light used, which can range from even lighting all sides to the use a single spot light on one side.
Here are some examples of how these two assignments were interpreted by students:
Want to try your own hand at photographing metal and reflective surfaces? Here’s what we recommend to achieve the shot:
- Zip Disks
- Calumet Tabletop Studio Kit
- Calumet PortaCube 50
- Trengove Studios Large Spill
- Calumet ZipBalance White Balance Reference Cards Kit
- Calumet Color Correction Tabs