Photography for Archaeologists Part II : Artefact Recording
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Photography for Archaeologists Part II : Artefact recording Guide 26 BAJR Practical Guide Series Lisa Jayne Fisher June 2009 © held by authors Photography for Archaeologists Contents Introduction 1 Coins 3 Flint 4 Pottery 5 Glass 6 Exposing correctly with a light-box 8 Colour temperature 9 Camera attachments: filters & close-ups 10 Use of scales 11 Bracketing 12 Building a copy stand 12 Further Reading & Other Notes 13 1 Photography for Archaeologists Introduction Artefact recording is another area in archaeology that is often overlooked and mis-represented. Not only does the archival quality of the resulting image matter but a simple understanding of lighting can achieve an enormous impact on the given textures, form and inherent detail of objects, giving valuable information which is often lost. Depending on the complexity of the artefacts’ shape, lighting can be experimented with by finding the best position and angle of the lights used for the job. It is often a laborious job to find the time to read up on the correct lighting positions for any given artefact. Often, it is far better to spend some time experimenting and observing, to find the best solution in any given situation. This will help you to judge artefacts by eye, leading to an implicit understanding of the qualities of light and should lead to sound practical experience, which should then become second nature. Simple lighting or copy stands can be cheaply purchased or rigs can be built out of simple materials utilizing desk lamps if your budget is limited. See final section on how to improvise with lighting. If in doubt about any exposure difficulties, it is always advisable to bracket any shots and this is good practice for all situations, even if you are using digital as well as traditional film cameras. See section on exposure for more detail. Below are listed some common artefacts that may require ‘special’ consideration and may be needed for publication purposes or simply to add to the archival record. This guide was produced by and copyrighted to Lisa Jayne Fisher www.vertical-photography.co.uk [email protected] 2 Photography for Archaeologists Coins These are fairly easy to record as long as the light source is controlled and observed well. As with any small finds recording, it pays to observe the little details and this can be done photographically by moving the light source around the object. This will help to determine the best angle of light for the subject. In this case, shadows and reflections are best minimised. Generally speaking, the lighting needs to strike the flat surface of the coin at a fairly oblique angle, approximately 45º. The camera is best mounted on a copy-stand, which places the camera on an adjustable column, vertically facing a baseboard below where the artefacts are placed. Such copy stands have small lights (usually tungsten bulbs), attached to a frame above the baseboard. These lights can be easily re-positioned to achieve the best angles for the job. However, before using such lights, it is advisable to read the section on colour temperature (or white balance with digital cameras), as you will get an orange colour cast when using colour film with this light source. Further consideration is needed when dealing with coins that have shallow relief marks. Recorded on a copy stand with the light at right angles (90º), such a coin would be rendered flat and lifeless. It would be advisable to bring the lighting to a more oblique angle, 30° may be better, so that the light creates longer shadows, giving greater contrast and relief. Figure 1. (far left) Lights positioned at 30º to the baseboard Figure 2. (left) Lights positioned at 90º to the baseboard As a final note, it is customary to place both sides of the coin in publications, with the obverse on the left and the reverse on the right. This can be achieved by using a multiple exposure function with a black background. With the camera on multiple exposure mode, the first shot records the obverse, which is then removed after exposure. The coin is then flipped around and, using a ruler to place it in the correct alignment, photographed a second time. It is best to consult your cameras’ manual for instructions on setting up multiple exposure modes. Alternatively you can digitally copy and paste the reverse of the coin through software programmes such as Adobe Photoshop. Fig.3 shows how effective this can be. Figure 3. The flip-side of the coin is digitally added to the original image 3 Photography for Archaeologists Flint Deciding upon which colour background to use is important and is dependent upon the colour and opacity of the flint being photographed. Lighter coloured, less dense flints would lose definition in the edges against a white background or light-box as the light would transmit through the flint. On the other hand, darker, more opaque flints would be lost against a black setting with the edges disappearing into the backdrop. It may be advisable to use a grey background or contrasting colour to the flint. In extreme situations, photographers Figure 4. have been known to paint the Opaque flint placed on a light- underside of thin flint edges, box gives little detail to prevent transmission of light through the surface, thus giving clearly defined edges to the side of the flint. This is quite a harmless process and involves painting the flint with an acrylic-based paint, such as artist’s acrylic or other water-soluble paints. This is easily removed after use. Figure 5. Lighting from above is a better Because flints are multi- compromise. faceted, it is best to view the artefact under differing lighting conditions before shooting, varying the angle at which the light strikes the surface by moving either the flint or the lights and constantly observing the shadows created for best effect. Viewing through a digital screen is ideal as you can see which lighting condition gives the best effect. Darker flints respond well to being placed on a light-box, with two lights at 45° to the lens axis on either side of a copy stand set up. However, caution must be taken to balance the lighting; if the light-box below is stronger than the light source from above you will get few details and a silhouette. See section below on exposing correctly with a light-box. The lights should be far away enough from the flint to minimise reflections on the glossy surface. However, placing diffusers over the lights to prevent reflections, would only serve to flatten the edges of the facets and would render the flint as a profile, with very little depth. Worked edges of flint can be photographed up close using a low single light at right angles to the lens axis, with the camera looking down the flint edge which can be angled to best Figure 6. effect. A better compromise with a light-box below and a stronger light on top to achieve a white 4 Photography for Archaeologists Pottery It is best to take care when setting up shots of complete pots as the angle at which the pot is placed in relation to the camera can make a big difference. For example, if the camera is positioned below the pot, the rim will not be recorded and the base will look enlarged and distorted (Fig.7). If Figure 7. the camera is looking down on the The rim shape is lost although pot, the base will not be seen and the the form is clear form is distorted (Fig.8). It is advisable to set the camera on a tripod with the lens axis slightly above the middle of the pot (Fig.9). This way, some of the rim will be viewed which will give the pot some depth rather than a flat profile. At the same time, most of the Figure 8. base will be recorded as well. The base is completely lost with a distorted form Convention usually calls for handles to be placed to the right with spouts to the left. Bowls are generally shot with the camera placed slightly lower than the mid-point to enable definition of the base to be clearly shown. Figure 9. Soft, diffused side lighting will give The best position is shot from good definition with surfaces that slightly above the body of the are incised or those that have relief pot or raised patterns on the surface. One diffused light at 35° to the side of the pot should suffice but if there is too much shadow on the other side a second, weaker light can be used to fill in the shadow details. Highly glazed surfaces are difficult to record due to the reflective quality of the lights being used. However, it may be necessary to show that the surface is, indeed, shiny. In such a situation, a diffused, single light to one side with a reflector (a large sheet of white card which bounces the light back) on the other side may prove sufficient. If the reflection is too strong, a polarising filter may be needed to minimise the surface reflection (see section on attachments). If photographing more than one pot, be careful when arranging them. Pots placed nearer the camera will appear bigger and those further away will appear smaller. They should not overlap and attention should be paid to shadows, which can obscure details on adjacent vessels. If you are recording pot sherds, differences in size and thickness can prove problematical. Care should be taken to arrange them with the rims at the top of the frame and the bases at the bottom.