Hi guys- thanks for the page.
If I was allowed to keep all the coins that I have photographed during my career, I would be a comfortably retired gentlemen photographer living in the lap of luxury. Alas, I had to give them all back to the collectors, dealers, the government, the mint and the museums that owned them. So now- I am just an old geezer photographer sluggin' it out with the new guys out in the marketplace. I still get lots of stamp and coin work so here's the drill:
There are basically two types of shots, the catalog or documentary shot and the adverting shot. Both types require the same lighting methods but the main differences is that the catalog shot is a straight on close up shot of the coin- front and back. The camera is placed directly over the coin at 0º, using a slightly longer that normal macro lens (best tool of choice) so that no distortion occurs and maximum sharpness is achieved. This kind of imagery is used for cataloging collections, insurance verification, transmitting or sending pictures to out of town appraisers for preliminary viewing and other kind of documentation and investigation.
In an advertising shot any angle of view can be chosen for the most creative and effective layout.
LIGHTING: In the photography of metallic highly reflective or polished objects, the angle of incidence theory is indeed the approach. The rule is: The angle of incidence is equal to the angle of reflection, however, you do not have to do the math, the geometry or get out the old protractor. Once you use the basic setup that I am going to explain herein, you will be able to do the rest by eye.
It is rudimentary that when we capture a photographic image, we are basically capturing the light reflected off the surface of what we are photographing. When we are shooting a mirror or a mirror-like surface we are capturing a mirror image of the light source itself- in this case we are, in theory, taking a (mirror image) picture of the front scrim of a large to medium sized soft-box – again the best tool of choice for this kind of work. If the light is, for example, placed at 45º to the camera/subject and the camera is also placed at 45º to the same axis,s the camera will SEE a bright reflection form the subject- this is called LIGHT FIELD LIGHTING. If, however, the camera is placed significantly off that angle, it may not SEE the maximum effect of the light source and render the object as dark or even black although there is a sufficient volume of light, this is called DARK FIELD LIGHTING. Both of theses results can be useful for various reasons and often where coins are concerned, the best lighting may be somewhere in between. If we were photographing a framed mirror, a light field lighting would render the mirror as white and the frame should record normally. If a dark field situation were to occur, the mirror may show as black, a shade of gray or pick up some reflection from stray light and show some color or detail and the frame can still be normally normally- as we see it.
Here's something else to think of. It's like when you are shooting a wedding and making the “mirror shot” of the bride getting ready for the ceremony. The camera and its on-camera flash are positioned at an oblique angle so you don't get flashback or take a picture of yourself in the mirror along with the bride.
OK- Coins are not totally mirror-like and some are more highly polished than others- some are even old, badly worn, tarnished, damaged and not shiny at all. In all cases, good rendering of the detail on the coin in terms of , texture, detail and relief are very important. Besides the basic angle of incidence approach, oftentimes a bit of feathering of the light, as we do in portraiture, is required to bring up the dimensionality of the engraving on the surface of the coin.
The basic setup is to place the coins on a table with a medium to large sized soft box equipped light source directly above them, ideally suspended on a boom type of light stand- this is your main light. Then roll the stand slightly to the back of the objects so as to create a small shadow in front of the near rim of the coin. Then view the object from the camera position while moving the light source incrementally, back and forth, tilted slightly toward the camera until the detail on the coin “pops”! You can rig an improvised setup without a boom stand, using a crossbar system, a wooden dowel, a shower rod or a length of PVC, ABS or metal pipe but delicate feathering may become difficult without a tilting mechanism of the kind that is incorporated in better boom arms. Being able to raise and lower the rig easily is important as well.
The next important pieces of equipment are a few reflectors- some white and some “silver” ones. Theses can be manufactured models but I make most of mine out of white Foam-Cor(tm) or the same material covered with aluminum foil that has been crushed and re-expanded. This allows me to have all shapes and sizes on hand to accommodate various jobs and layouts. Theses reflectors can act as fill light sources, kickers to accentuate the rims of coins or further enhance relief and even extend LIGHT FIELDS when required.
The attached image is, in fact, an advertising shot but I chose it for a number of reasons. If you will notice, there are coins in both gold and silver, mostly in light field lighting conditions. Their are 3 coins that, because of the way it was tilted on the set, is in dark field. With feathering, some of them are kind of in between. This goes to illustrate how a slight change in angle of incidence coordinates can incrementally or radically change the interpretation of the subject. This is where the old eyeballs factor in.
A few tips: Many coins are incredibly valuable beyond face value due to age, rarity, historical value or collectors market circumstances so they should be handled with extreme care. In many cases it is permissible to clean the surface of the coin to remove fingerprints, soil or smudges with a soft cloth or a jeweler's polishing cloth which may be impregnated with a mild cleaner . Never apply any kind of detergent, cleaner or solvent without permission of the owner. There are certain acids that can reveal worn off detail on coins but all of theses materials should be only applied by experts. Some coins must be photographed as is with dirt, smudges, tarnish and who knows what sill clinging to the surface.
Backgrounds: These are my picks- Black velvet- it eats light and will create jet black background. For a pure white shadow less background, I place the coins on a sheet of SIGN-WHITE Plexiglas and illuminate the material from beneath- colored filters (gels) can also be used in this setup. Another approach is to place the coins on a clear sheet of glass suspended over a sheet of gray background paper at a distance of about 12 inches. You can light the gray material with white or colored light- this sub-background will be sufficiently out of focus to create various effects and in both Plexiglas and clear glass methods, with trans-illumination from underneath the set, there will be no shadows surrounding the edges of the coins. For ad shots you can also stand coins on their edge and use a reflector to kick in light to accentuate the edges.
For a flatter less dramatic effect you can also build a tent by sou rounding the coins with white reflectors and still using the overhead soft box as your main light source. There are also a few manufactured tents where you place the subject under the rig and bring in your lights from the side. I find theses units somewhat practical but not a versatile as my main method.
Well- dats all folks- any questions or remarks- all welcome. Good luck! Diagram will follow in next post!