Lighting a diamond and other small objects.
 

I'm building a revolving stage for shooting small objects, that's simple enough but what to do for lighting. One of its first jobs could be shooting a single tooth in black limbo. I'll need plenty of light to get enough DOF so I'm thinking those fibre optic wands that I used to use with a stereo microscope might be the way to go but they're expensive so other ideas welcome.

One problem with lighting the object(s) is avoiding specular highlights, we don't want any clipping as we need accurate color rendition so on the other hand tiny point light sources wouldn't be the way to go but relatively large sources means light going everywhere which leads to my next issue.

My other problem is finding a finish that's as black as possible for the revolving stage and background. I've found a kind of matte black engine enamel that because of it's finish is better than most matte black paints however I've noticed a really black finish used inside matte boxes that really sucks up the photons, something like that in a paint might be better.

The approach for a diamond and for a tooth would be pretty different.

That's because one is largely transparent, while the other is largely opaque.

First, decide what aspect of the object is important.

For the tooth, it might be the surface (e.g. restoration work, cavities, cracks, etc.) - the shape (cosmetic reconstruction) or even the color (bleaching and other similar cosmetic treatments)

So you're lighting approach needs to be based on bringing out the aspects of the object that are most important to the client.

With a diamond, same thing. What's important? If it's the cut - then you probably want to emphasize the facets. If it's the clarity - then you want light shining through that creates a contrast.

One key is to understand that transparent objects are exactly that - transparent. Unless you have something to see that's BEHIND the object, they don't really show up well.

Same with shiny metal anything. You're often not actually shooting the thing - you're shooting what the thing REFLECTS.

As you see, jewelry takes a good bit of practice. Google tabletop photography and jewelry photography and start studying up. Then set up things and practice, practice, practice.

Oh, and paint is often a hassle unless it's VERY well applied. Small drips and inconsistencies can become huge when you're working with a close up diopter. Think FABRIC for your background. Duvytyne is nice, Silk, satin and velvet are very rich but it's also somewhat reflective , so you have to set it up and light it carefully, but the play of light on the surface of say, velvet can be quite beautiful. Also give some thought to mounting and holding the objects. That's often a real challenge with small object videography.

Good luck.

Black cloth, preferably velvet, for the background. You can't clean a matte-painted finish without changing the surface luster, and you can't retouch portions of the paint without leaving a visible mark. Plus, you can tuck support items under the cloth to prop the items you're shooting.

Martin

Back in the 80s I had a client that published a jewelry catalog and we’ve done hundreds of jewelry shots. It was still photography but we also applied the same lighting techniques later to film and video. We’ve done it with mirrors. Project the light into the mirrors and direct the mirror into the product. There’s no way that you can direct lights toward a small object and avoid tons of unwanted spills. Mirrors will give you a sharp beam of light with no spills wherever you need it. You can place mirrors anywhere that you wouldn’t dare place a light. You can use concave or convex mirrors to concentrate or spread the light and you can mask the mirrors with black gaffer tape to create any shapes of light you need. As far as getting enough light to give you enough exposure is really up to the quality of the camera and the speed of the lens that you are using. As you’ll be shooting extremely tight on the object the light from the mirrors don’t have to travel very far so there will be minimum loss. You can find a large selection of inexpensive mirrors at any scientific surplus stores; most of these mirrors are used for laser experiments and are available in all kinds of shapes and sizes. We used to get them from Edmund Scientific. Make sure that they are front coated mirrors not the back coated like regular mirrors; front coated will give you maximum and accurate reflection. You will need some sort of clamping to hold and direct the mirrors precisely where they are needed. Some mirrors come with their own stands or you can use inexpensive “Helping Hand” holders used for soldering.

Remember that transparent items such as glass, or diamonds in your case, need transmitted light from the back to better show all the details. The shape and details of the object will bend and reshape the transmitted light. The reason that we can see any opaque object is because the light reflects off of it. On transparent objects front light will go right thru it.

As far as background goes there’s no black material that absorb light 100%. The reason that you see black is because even black reflect some light. If the exposure allows it a polarized filter will eliminate any reflection and the background will disappear. You might also consider playing with the pedestal setting on your camera below the standard 7 IRE, as this will lower the value of the blacks and increase the contrast of the image; this might improve the overall picture.

Thanks everyone, especially Nino.
Edmund Optics have everything, what a resource. I like the idea of using mirrors however their fibre optic wands and illuminators will be much easier to work with, quite a range here:http://www.edmundoptics.com/onlineca...categoryid=243

They also have a light absorbing flock paper material http://www.edmundoptics.com/onlineca...productid=1502

Nino also got me thinking outside the square. As I control how the subject moves there's no real reason to even use a video camera, all that's needed is a steeper motor to turn the subject, turn, click, turn, click etc. A DSC gives a wider choice of optics and exposure times.