Lighting glass, part 1

I asked a question about these tutorials on Talk Photography, to find out what people are actually looking for in lighting tutorials, and some of the members said that they would like to see tutorials on
  1. Lighting glass
  2. Using an absolute minimum of equipment
  3. And doing it in a tiny space
Well, that’s fine, because glass is actually much easier to light than most people think, it needs very little in the way of equipment and it can be done in a tiny space, so I thought I’d do a simple tutorial showing how to photograph glass in a small space with hardly any equipment – the  total size of the set used here, excluding the camera distance, was just 1.3m x 0.9m…
In reality, the only actual problem with glass is that it’s transparent, so the only bits of it that can be photographed are the bits that interfere with the passage of light in some way – any m0uldings, engraving etc on the glass are visible, and so are the edges, which refract the light due to the differing densities of the air and the glass. Of course, if the glass item is a container of some sort, then any contents will also interfere with the passage of the light and so will show on the photo.
But there are other things that can be photographed too – scratches, dust and fingerprints – so cleanliness is absolutely essential.
To make the process even simpler, there are only really two ways of lighting glass (although these methods can be combined, or added to)
1. Darkfield
2. Brightfield
Darkfield lighting involves lighting the glass and nothing else, Brightfield involves lighting the background and not the glass, these techniques are not mutually exclusive and can be combined in the same shot,  and both techniques are simple. Which technique is ‘best’ depends on your personal preferences as well as on the subject itself. I will deal with brightfield lighting in this tutorial, the one on darkfield lighting is here.
For my subject, I used a handy and nearly empty bottle of after shave. It has a fairly complex shape, with various bulges, convex and concave surfaces, so it’s bound to create a fair bit of refraction.  As always, it came with an illegible label on the back. I can’t read the tiny type, probably nobody who is old enough to actually use the product can, but having it there when I photographed it would be distracting so, as always, I removed it. All of the branding on the front also takes the form of labels. That’s a pity, it would photograph better if the branding was integral to the moulding. It still has a drop of that green smelly stuff inside…
When people photograph glass without trying very hard they usually crop off the bottom of the subject. This makes life easier, but in these example shots I’ve shot ‘full length’. Full length involves including whatever the object is standing on, for these shots I used a few sheets of white A4 paper. To get them to photograph as pure white I would have needed an extra light on the paper, but because we’re doing it with the minimum of equipment I didn’t bother – it’s a very simple matter to sort that out in Photoshop, which I did on the photo shown on the left, all other photos are ‘as shot’.
My setup here is a corner of my studio, with a small table (covered in white paper) in front of a softbox. The softbox is fitted to a flash head. Any kind of light, for example a continuous light, could have been used instead of the flash head.
My camera was fitted with a 200mm lens, I could have managed with even less space if I had used a shorter focal length. The camera was mounted on a stand, and behind the camera and a bit to the right I mounted a second camera, which produced the setup shots used in this tutorial. The setup camera was just set to P (for professional :)) mode, to record what I did.  Small changes were made to camera and subject positions, so not all shots are identical in terms of position.
As always with my tutorials, all of the shots below are straight out of camera, other than re-sizing. I don’t retouch or manipulate tutorial shots. Click on any photo to see a larger version.
It’s easy enough to meter the light, but as not everyone has a meter I didn’t bother, it isn’t necessary for this type of shot. I shot at f/16, to give me enough depth of field for the angled shots. Here’s the very first shot, photographed with the setup you see above. Obviously the area near the bottom needs to be retouched out, but I’m not concerned about that. What I am concerned about though is that the softbox is lighting far too large an area, this causes light to go where it isn’t wanted, including into the lens. My lens is of course fitted with an efficient lens hood, but we still need to reduce the area of the softbox.
And the best tool for that job is Cinefoil, a trademark of Roscoe. Cinefoil is basically just thick black cooking foil, coated matt black both sides.  It’s wonderful stuff and absolutely invaluable in the studio. I hardly ever throw any away, once it’s creased up it can be flattened and re-used, which is what I did here. My first job was to mask the areas of the softbox that weren’t needed with Cinefoil. Just bend the edge over the softbox to keep it in place, or if the piece of Cinefoil turns out not the be flat after all, as in this case, use a clamp to hold it in place. If you don’t have Cinefoil, black card will do the job.
This has made a difference to the shot. It’s subtle but it’s there.
But the shot is still horrible and bland, something needs to be done to inject some life into it, and once again that something involves Cinefoil.
I used some more Cinefoil  as an absorber, I just needed a piece of it either side of my subject, and only just out of shot. This makes a huge difference, as you can see.
There are all sorts of ways of putting stuff like Cinefoil in the right place, here I ‘covered’ a couple of hardback books and just stood them up, it’s all that’s needed.
This shot, closer and from a different angle, may help.
So what else is left to do? Well, it’s possible to fine tune every shot and find ways of making small improvements, or at least to make some changes, and in this shot I simply rotated the bottle to a different angle. But I had to do a little bit more than that, because changing the angle meant that I needed to re-position the black absorbers, as in the shot on the right.
Subjects such as cut glass, or coloured glass, or glass with mouldings or complex shapes are easier to photograph well, but the principles are the same.
Some subjects can present special problems, and this beer glass (don’t ask) isn’t really the easiest because the side (or in this shot, the top) can easily disappear into the white background.
Again, this is easily solved just by using a piece of Cinefoil above the item, just out of shot, to create a dark edge that helps to define its shape.
The difference is worthwhile, I think.
For something as simple as this, the easiest way of ‘fixing’ the Cinefoil in position was to set the camera on self-timer and simply hold it where it needed to be.
Just a couple of pointers…
  1. With all types of photography, camera height is very important. With brightfield lighting of glass, it’s even more critical because if you’re looking down on the subject at all (as I did here) then the product base, where the subject is resting, will show through the glass and involve you in retouching work.
  2. Absolute cleanliness of the glass surface is critical, it will show every mark. The particular products photographed here had been lying around for a while and were old, but really you need to photograph new items, after cleaning them thoroughly.