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 examples 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 transparent and translucent glass surfaces:
The purpose of this assignment is to introduce students to the problem solving involved in photographing transparent or translucent subjects.
The goal is to produce two extraordinary photographs. The subject could be the same for both shots.
- Shot 1: Black Line Lighting Pattern (Figure A)
- Shot 2: White Line Lighting Pattern (Figure B)
It is important to keep in mind that the light we see through the subject(s) and reflected off of the edges is what gives the subject its character and form. In Figure A light passes through the subject from behind to the camera. This light does not have the angle required to reflect light off of the outside edges of the subject. Black cards are positioned to reflect off of the outside edges allowing the clear subject to separate from the white background.
When positioning the black cards, it is worth noting the 2nd Law of Light: the angle of incidence is equal to the opposite of the angle of reflectance.
A quick test of this lighting concept can easily be seen by holding a glass subject positioned with a window in the background. Watch the changes in the edges of the subject as you move closer and further away from the window. The walls on either side of the window will function as your black cards. Notice that the relative distance from the window will change the width of the black edges of the subject.
When making your initial light reading, it will be off of the diffusion material – not the subject. We want to know the brightness level of the light source – not the brightness level at the point the light hits the subject. If you are taking an incident reading, hold the light meter against the diffusion material. This reading will give you a white background. If you are taking a reflective reading, remember that the meter is giving you a reading for a middle-tone gray. Test several brightness levels for the background light source to see what might give you the best qualities for your specific subject.
Figure B illustrates the lighting pattern for White Line. In concept, it is essentially the opposite of the Black Line setup. A black card is placed behind the subject, blocking light from passing through the subject to the camera. On either side of the black card are the light sources that will reflect off of the outside edges of your subject, separating it from the black background. This lighting concept can also be tested by holding a glass subject with windows in the background, except in this case a wall will be directly behind the subject with windows to the right and left. Again, notice the changes to the edges of your subject as you move closer and further from the wall.
Note: If you have the subject too close to the background, you will be cutting off the angle needed for the light to reflect correctly from the edges of your subject.
Also,for best results, flag light off of the lens in both lighting scenarios.
Student Work Examples:
- Nicole Nesmith used the Black Line concept by allowing the background light source to reflect off of black Plexiglas back to the camera. Small mirrors were used to catch some of the main light and reflect it back into the label and mint leaf.
- Daniel Andres used the White Line lighting pattern in conjunction with a separate light source with a blue gel. The top rim of his subject has a highlight around it because he didn’t cover the central area of his light source all the way to the top. The white area at the upper area of his light source can now reflect of the top surface. If he had covered the central area of the main light source completely the upper rim of the subject would be black.
- Megan Bedford used green and blue gels to achieve the desired effect. Light was allowed to hit the subject directly as well as reflected from below.