The word photography literally means “drawing with light.” What is seen by your camera lens is “drawn” on the sensor by the light that is reflected from the subject. It is the reflected light gives the form, texture, color, etc. to the subject. Most of the subjects that you come across are opaque. That is, they reflect light but do not allow light to pass through them. Glassware on the other hand is transparent and hence has the unique property of transmitting light through it. This singular ability of glassware to pass through light presents some very interesting possibilities and challenges in photography.

Being transparent glassware lends itself to be beautifully backlit. With colored light, glass can produce images that no opaque objects can. The possible combinations are endless, limited only by the imagination of the photographer. This is what makes photographing glassware at once a challenging and a fascinating subject. Glassware photography is a subset of table top photography but it is the trickiest of the lot. In fact it is jocularly said that glassware photography assignments are given to students only by sadistic professors! In this article you will be introduced to some important concepts that you can extend to more complex situations.

A truly transparent subject cannot be easily photographed because it will be invisible! So how do you make the invisible glass visible? This is the challenge presented to you as a photographer. Also note that glassware is highly reflective apart from being transparent. A reflection from a glass surface will obviously declare the presence of glass but these reflections are highly specular and small in size. Hence, these do not reveal the form of the glassware. In fact reflections from glass are generally unwanted. The only way to render glassware and its form is not to record the surface of the subject as you would normally do but to record the edges. For this we need to exploit the property of transparency.
Before you proceed just remember what you learnt in your high school physics – angle of incidence of light is equal to the angle of reflection. I am sure that you have seen the diagram shown here previously. However, this is a much simplified diagram (compared to a real world situation) as it shows just one light ray incident on a flat surface. In practice there will be infinite light rays. Plus glassware generally has curved surfaces. Due to this any light incident on a glassware surface will reflect in all directions. Hence, it is indeed a tricky task to light even a simple glass without reflections. You can only achieve this by placing the light source very carefully where it cannot create any reflections. The diagram shows where you need to keep the light source to get such an effect. Note that you have only a very narrow area where you can keep the light source. While this looks quite restrictive you can get two complementary effects with the same light. How is this possible? Read on.

The two methods used to get these effects are called bright field and dark field techniques. The first renders the edges of glassware as black and second as white. It is technically possible to combine both the techniques in one photograph but this is a bit complicated and we will leave that for another day!
Bright Field Technique:

The lighting setup is shown in the diagram. One way to setup is to use a soft-box or a table lamp with a sheet of translucent material like tracing sheet in front. You will need a stand with a platform to keep the glassware in front of the light. The platform can be a sheet of glass or translucent acrylic. This will allow some light to pass through the platform and the base of the glassware brightening it. Another way is to use an acrylic sweep. This will be similar to the sweep used in table top photography (refer to Basics of Photography, Smart Photography, August 2010 issue) but is made of translucent acrylic. Alternatively you can also buy a gadget called light table which gives you this functionality.

Next step is to position your camera at the right place. This is a critical requirement and needs to be done before you keep the subject. After you choose a lens of suitable focal length you need to move the camera front and back so that the (angle of) view as seen through the viewfinder exactly covers the background, which are the edges of the soft-box (or whatever you have used). If this is not properly done then you will not get the desired effect. If the field of view is smaller than the background then you will notice that you will start getting unwanted reflections on the edges of the glassware. This is not what you want since in bright field technique you need to get dark edges. If the field of view is larger, then your camera will start recording an area beyond the background.

Now keep the subject on the platform. You will notice that as the subject is moved away from the light source the edge definition improves as there will less light reflecting from the edges. Find a suitable position for the subject and then focus.

You are now ready to take the photograph. But what is the exposure that you need to set? To understand that remember the metering “mantra” that you read in Basics of photography, Smart Photography, July 2009 issue. The mantra says that metered area is always rendered as medium tone but you can place it at any tone you want with proper exposure compensation!

With the bright line technique you already know that you need to keep the edges dark than the background light. Your exposure will determine how the background will be rendered. Rule of thumb here is that you can keep background around one stop lighter than medium tone to keep contrast with the edges.

If you are using a continuous light source, then switch to spot meter and then select manual exposure mode. Take a measurement of the top portion of the background and set it to 1 to 2 stops lighter than medium tone. You can experiment a bit to arrive at what pleases you most. If you are using a strobe light then you need to use a flash meter or do some trials with the help of histogram shown in your camera to get the right exposure.

Note: If you are keeping the subject on a platform and since the background is lit, there is a chance that the edge of platform will be recorded. This is not aesthetically pleasing. The easiest way to avoid this is use a sweep made of translucent acrylic as it was done here. This will give you a seamless background and will also help you to illuminate the background as well as brighten the glassware from beneath.

Dark Field Technique:

The lighting set up is shown in the diagram. You would have noticed that it is similar to the lighting of bright field technique, but for a gobo placed between the light and subject. The gobo is just a black opaque card which gives the black background. Its size should be such that plenty of light is visible around it. Here the size of the light source is very important, the larger the better. It should be preferably 10 times the size of the subject. The subject also needs to be kept on a black platform.

As in the previous case the positioning of the camera is very critical. After you choose a lens of suitable focal length move the camera front and back so that the (angle of) view as seen through the viewfinder exactly covers the background, which is the black gobo. To reiterate, this is very important! If the angle of view is smaller than the black background (gobo), then the gobo will block the lighting falling on the edges of the glassware. This will render them dark and they will merge into the black background. If angle of view is larger than the gobo, then your camera will record an area beyond the black background which in this case is bright light.

Now keep the subject and focus.

Determining the exposure in this case appears tricky since the scene is predominantly black. But you are really interested in the highlights on the edges. Remember that the direct reflections are as bright as the light source itself. So, if you are using a continuous light source, simply take the reading of the light source (put your camera in the spot meter mode and manual exposure mode first). This as you will recall will make the light source appear as medium toned which is not what you want. Giving an exposure compensation of 2 EV (stops) will render it close to white and hence edges will also be rendered white. You can experiment around this value and get the ideal exposure. If you are using strobes, you need to experiment a bit, taking the help of histogram.

Tip: You may be surprised to note but most D-SLRs (except high end models) do not have very accurate viewfinders. They show a little less than what is actually captured by the sensor. So, if you frame exactly using the viewfinder you may not get the results you want. On the other hand your camera’s LCD monitor is very accurate and corresponds to 100% of what is being captured. So, it is better to switch on the live view mode of your D-SLR and use the LCD monitor for viewing.

Subjects: One great advantage with glassware is that every household will have some basic glassware for you to start. Even simple glasses will look nice and are a good starting point. If you have wine glasses they would make an ideal subject due to their shape. Apart from these standard items, cut glass and glass figurines also make excellent subjects. One caution: high quality glassware (especially cut glass, crystal ware, etc.) can be expensive. Please handle with care. Broken glassware can cause broken heartsJ!

Tips for light sources: There is a real need for large light sources in glassware photography. If you have a slide projector from your film days, you can make an excellent large light source with it. Project the light without any slide on a screen or a white wall and use the entire illuminated surface as a large light source.

If you have a LCD computer monitor you can get a light source by opening a MS-Word or Notepad file with a blank (white) document. You can even get colored light from the LCD monitor by choosing a colored background (instead of white) in the software. A tracing sheet can be taped in front of the monitor if you need more diffused light.
Alternate lighting techniques: While the bright field and dark field are the most popular, there are several other techniques that are useful in lighting glassware. Here is one such method. This is most suitable for glass statues. The lighting is done from underneath the subject and since glass is transparent the whole subject lights up. No other lighting is needed.

Here, the statue has been placed on a sweep made of opaque black paper. Since you need to light the statue from beneath, you need to cut a hole in the paper with a contour similar to that of the base of the statue but slightly smaller. This will prevent light from leaking out and will ensure that the light is fully confined to the statue. If the cutout is larger, then some light might spill out through the gap between the base and the cutout in the black paper. Since you are lighting from beneath, you need to keep the paper on a glass table or surface. You can also keep gels or cellophane paper in front of the light to get colored lighting. The other end of the sweep should be held vertical so that it will form a seam less background. The statue much be kept exactly on the cutout and should completely cover it.

Monochrome or Color? The examples you have seen so far have all been rendered in monochrome (black and white). While this is the best for color-less glass you can also take wonderful pictures of colored glassware. This image shows one such photograph. The lighting set up used here was identical to the bright field lighting technique shown earlier. The exposure reading was taken of the background as before and the compensation was set to +2.0 EV so that the acrylic is rendered in its true tone which is milky white.

Equipment needed for glassware photography:

· Glassware photography needs minimal equipment. Any digital point-and-shoot (or a bridge) camera with macro capability or preferably a D-SLR with a close focusing lens (that is, one with a moderate macro capability) will do the job perfectly.

· Precise positioning of camera that has been described can only be achieved by using a sturdy tripod. Don’t try handholding and get frustrated!

· Expensive lighting equipment is really not needed. A simple table lamp with a compact florescent lamp (CFL), (See Basics of Photography, Smart Photography, August 2010 issue) will do the job perfectly. Alternatively strobes can be used. You can use portable shoe mount flashes too but these can be a little difficult to use since they do not give continuous light or have modeling lights. You must also have the facility to keep them off camera and trigger them. Remember that you just cannot photograph glassware by mounting the flash on your camera’s accessory shoe.

· Thick black matt paper.

· Cellophane papers of different colors in case you want colored light

· Translucent acrylic milky white sheet (2mm thick) of 4ft X 2ft dimensions for forming seamless back drop behind which light is kept. (Acrylic sheets are normally used for making back lit signboards and are available in hardware shops).

· As you can see, besides the equipment that is needed for general photography, i.e. camera, lens, tripod, the extra equipment that is needed to produce the photographs shown costs very less. So, this is a type of photography that can be easily attempted without busting your bank account.

Some important precautions you need to take:

· The glassware you are planning to photograph must be squeaky clean! You will be surprised how well the camera can capture blemishes like water marks, finger prints, etc. even if you haven’t observed them.

· The room must be absolutely dark without any stray light. This is very important as stray light causes unwanted ugly reflections.

· The room in which you are photographing must be completely free of reflecting surfaces (window panes, glass shelves, etc.). In case they are present, make sure that you have covered them so that there are no unnecessary reflections.

To conclude glassware is an exciting but tricky subject. However, it requires only minimum investment in terms of equipment. Subjects are easily available too as every household will have some glassware. Follow the procedures outlined in this article and you can have endless hours of fun. Plus you can get results that you will be proud to show to your friends and family. Good luck.