BACKGROUND SELECTION Typically, a black, nonfluorescent

back-ground is used so as not to distract from the subject. Black velvet is most often used, but lint on the cloth can be a serious problem. The lint fluoresces a strong blue/white and can be difficult to com-pletely remove from the background.

Clean the background thoroughly using tape to dab off the lint, or use a commer-cial rolling lint remover such as can be bought at the supermarket. You can also minimize the lint problem by elevating the subject off of the background (in a copy-stand arrangement) by means of a

hidden pedestal. Another problem with black backgrounds is that if the fluores-cent mineral is in a dark, nonfluoresfluores-cent matrix, there will be no outline of the specimen-the fluorescent mineral will appear to be a disconnected series of lights in a sea of black. Some photogra-phers deal with this situation by placing the subject on a colored paper or card-board background that fluoresces a subtle but contrasting color. Experiment with different materials under the UV light to find a pleasing background. White papers are not used because they nearly all fluo-resce a very strong blue/white due to added brighteners.

Modreski (1989) suggests another technique to separate the subject from the background. Briefly light the subject with white light after the fluorescent exposure. The result will be fluorescent patches on a dimly lighted matrix. You must be careful when doing this because the white light exposure will subdue the fluorescence and reduce contrast.

I have found that a double exposure technique works well for producing con-trasting backgrounds. I place the speci men on a sheet or raised glass as shown in Plate 25. The background paper is illumi-nated with a spodight or microscope light as 1 would normally illuminate a shot.

The first exposure is taken with just the background light on, and the second with the background light off but the UV lights on instead. Some experimentation will have to be done to determine the proper relative exposures of the two lights, along with a lot of bracketing.

A tripod or copy stand is a necessity, as is a locking cable release. Compose the photograph using whatever lights you would use for a normal photograph, then turn them off. Lock the shutter open on B, and time the exposure using

a watch with a sweep second hand or a digital watch in stopwatch mode, then Glose the shutter.

OTHER

CONSIDERATIONS

Different materials have dramatically ferent levels of fluorescence. These dif-ferences can be a problem when shooting several specimens at once, or when sever-al different fluorescent minersever-als are pre-sent in the same specimen. If not com-pensated for, you will find that some of the colors are overexposed and washed out, and others too dark and underex-posed. The simplest way to deal with this problem is to compromise on the expo-sure and choose the one that is inbetween the two extremes, while the best way to deal with the situation is to mask the brighter arcas if possible, placing black cardboard outs over them. The cut-outs are removed part way through the exposure to achieve a more even sure. It's best to learn the relative expo-sures by making trial expoexpo-sures of the subjects individually.

You will also find that some fluores-cent colors do not record accurately, even with proper barrier filters and no reci procity failure. Film emulsions don't

"see" things exactly the way our eyes do, and are also designed for use under more

averáge conditions. Most films are bal-anced for common colors such as rich greens, skin tones, black, gray, and white.

They deal less accurately with pastels, pinks, purples, and oranges. To learn more about this problem, see Kodak's publication number E-73 (1987). If you run finto a film sensitivity problem, you can deal with it by using color-compen-sating filters in the procedure described in Chapter 10. This method doesn't work well if you have more than one fluores-cent color in the shot, as other colors will be inaccurately changed due to use of the CC filten

If you're going to work for prolonged periods with UV radiation, use protective eye wean Sunglasses that block UV can be used, but a better choice would be contrast goggles designed specifically for the purpose. They are available through a number of UV equipment supply hous-es. In blocking stray UV radiation, they also serve to increase contrast when view-ing fluorescent materials. Never look directly into UV lamps, as they can permanently damage your eyes. You should also keep your skin covered when work-ing with UV for long periods to avoid sunburn.

151

It's often handy to photograph a sub-ject in normal light as well as UV for comparative purposes. If you use the same daylight film for both, you must consider the color balance for the nor-mal shot. There are several options for dealing with the different requirements

for the two shots. You can use blue day-light photo flood bulbs, dayday-light studio flash, or a conversion filter over the lens.

If you have two camera bodies, you can use tungsten film for the normal shot and daylight for the UV shot.

I n many ways, the photography of lapidary materials is the same as that of minerals. There are, however, some major differences. The peed for accurate, detailed photography is the same, but the subject in lapidary photog-raphy demands different treatment.

Minerals are essentially viewed by them-selves and stand or fall on their own mer-its. Most mineral collectors tend to be purists and insist that specimens be por-trayed without a lot of window dressing.

Lapidary materials seldom stand alone.

Many pieces are functional and are used within specific contexts. The person on the street may not know exactly what the stones in a piece of jewelry are, but he or she knows the beauty, aura, mystique,

and, perhaps, the history of a piece.

Therefore, lapidary materials are seldom presented without window dressing.

The use of photography to promote a piece demands that the subject be placed in a setting that entices the viewer and creates a mood of elegance, mystery, or beauty. Although the photography of minerals is very rewarding and creative, photographing lapidary materials is much more challenging and demands more of the photographer's creative and design talents. If you're doing advertising photography, the work you do must be constantly fresh and creative. In the high-ly competitive jewelry business, clients don't want to see their ads look like some-one else's, or not stand out on the pape.

This chapter deals with the specific requirements of photographing lapidary materials. Many of the general techniques discussed in previous chapters-such

as those pertaining to equipment, film, light sources, metering, magnifications, and medium- and large-format photography-apply as well and the reader is

referred to those chapters for the basics.

(See also Chapier 18 on location shooting.)

153