Glass can be a difficult subject to photograph – or at least a difficult subject to photograph well. With reflections from many directions, it can especially seem difficult to control the lighting so that the glass looks realistic. Thankfully, by following a set of some simple rules, it can be conquered. This photograph was one of my first attempts to tackle the subject.
I was guided in my experiment by a very good book about lighting called Light – Science and Magic, which takes quite a scientific approach to light to explain the theory behind lighting a varied range of subjects. The thinking is that if you can understand the theory – particularly the physics of light – it’s easier to deal with light in your photography. As well as the theory, the book sets out some simple steps to follow for different subjects.
This image illustrates one fundamental point about lighting glass very well as explained in that book. When it comes to glass, more often than not, lighting it is not what’s important. It is not lighting it that is key.
The setup here is glasses filled with water (some of it dyed with food colouring), sitting on a glass surface, beneath which lies a sheet of white paper. Another sheet of white paper hanging as a backdrop. The glass/paper surface itself sits on an ironing board (it was nearby and height adjustable which helped a little with framing the shot). The entire set up is in a darkened kitchen.
The photograph is lit with one just bare flash.
I mentioned that “not lighting the glass” is the key point to remember. The SB-800 I’m using to light this setup is sitting underneath the ironing board, pointing at the background, with no line of sight between the flash and the glasses. All the light in the image is therefore being bounced off the background. Any other technique for lighting this shot will most likely leave large reflections of the flash(es) used on at least one of the glasses.
Before the shot is lit, a key thing to set up first is the background. The background must be just large enough to fill the entire frame, and no larger. I achieved that by first putting my camera on a tripod with a 50mm lens, putting the ironing board with the glasses such that I got the composition I desired, and then moving the background far enough back to just fill the frame. With the background in this position, once we flood it with light it will provide a suitable backlight for the glasses, and the fall off in light between the background and the darkened (unlit) kitchen will be reflected in the edges of the glasses and give some definition to those edges.
With everything in place, the rest is straight forward – adjust the flash output so that the background is adequately lit, and with the aperture set correctly for a good exposure, the image falls into place quite easily. In post processing I actually added a slight vignette to the end result. One thing to note is that when you add liquid, the defraction of the light can change the rules slightly, and I would have had a better result if I moved the background back a tad further, so that I didn’t get the thick dark edges most noticeable in the blue glass. Still – not bad for a first attempt if I do say so myself.
Update: A commercial photographer who saw this as a printed image recently informed me that moving the background wouldn’t necessarily have helped with removing the darkness from the edges of the glass. Martini glasses in particular have a natural prismatic effect on light, and this is an issue that commonly arises in commercial photography when using them. He also told me that the most common fix, if the shot allows for it, is to put fruit or other such objects into the liquid to break that prismatic effect, and that helps with maintaining crisp edge definition on the glass.
I happen to like that thick edge, it adds some depth to the photo.