Photographing artifacts has been a recent topic of discussion in the Castle Museum Archaeology Lab. Last week it was suggested to me that some might find a basic description of my methods helpful. I should say up front that I make no claims of photographic expertise, or even above average competence (readers can peruse the photos in previous posts and judge for themselves). However, I rarely (never) get requests to do a blog post so I could hardly turn down the invitation. Others are sure to have useful tips and suggestions. If so, please share!
Whether they appear in publications, presentations, blogs, or Facebook posts, photographs are an essential means of communicating about artifacts we have found or are studying. Good photographs can reveal at a glance general attributes such as size, shape, and color. They can also show difficult to describe details such as textures, flaking patterns, or tool marks. And, they can even be aesthetically pleasing! On the other hand, bad photos are often unhelpful and can sometimes be downright misleading. Not all photographs need to be works of art, but most good artifact photos share the following traits: a scale, a clean monochrome background, and low angle lighting.
Here is an example of a photograph that could be much better. It lacks a scale so we have no idea of its size, the background is messy, and the overhead lighting does not bring out the details of the surface treatment (click on photos to enlarge).
Here is an improved version of a photograph of this Late Woodland grit-tempered ceramic sherd from the Stadelmeyer Site (20SA195) in Saginaw.
This is how I did it:
I always use a copy stand. A copy stand provides solid support to eliminate camera shake and allows the camera to be kept a fixed (adjustable) distance from the artifact so that multiple artifacts can be shot at the same scale. My copy stand is cobbled together from pieces of a commercial copy stand bolted onto a light box with a rheostat to control the light intensity. The light box can be useful for producing artifact photos with a white background and no shadows. However, I rarely shoot pictures this way anymore. Instead, I prefer to use a black cloth draped over the light box for the background.
I use a single directional light on an adjustable light stand. The light is set so that it originates in the top left corner of the frame. A piece of white foam core positioned just of the bottom right of the frame is used as a reflector for fill light. Low angle lighting is generally best for showing the details of artifact surfaces. Every artifact is different so you need to adjust the height of the light and the position of the reflector to your best advantage.
Here is one more example showing a side-by-side comparison of overhead vs. low-angle lighting. This is another Late Woodland grit-tempered ceramic sherd from the Stadelmeyer Site.
Always include a scale in the photo. I have five and ten centimeter scales that I made out of cardstock and foam core. A small ruler would also work. In a pinch use a familiar object such as a coin, but always include a scale! In the following photographs, which biface is larger? Without a scale we have no way to tell.
Here are the two bifaces side-by-side with the appropriate scale.
Bright lights, a black background, and variously colored artifacts can wreak havoc with a camera’s light metering capabilities. I set my camera to use spot metering directly on the artifact and use exposure compensation as needed. Even with spot metering, the black background often causes the camera to overexpose the artifact necessitating negative exposure compensation.
I usually set the ISO to 400 or less (often 100) to prevent excessive noise, or grain, in the image. I shoot in Aperture Priority mode, which means I choose the aperture (usually F8 or F10) and the camera picks the appropriate shutter speed. Because these settings often result in a relatively slow shutter speed, I use the automatic timer with a two second delay. A remote shutter release would be better, but I don’t have one and the timer works fine.
Finally, I usually shoot in RAW rather than jpeg. If things don’t come out exactly right the RAW format gives me a little more flexibility to tweak the white balance, bump up shadows, reduce highlights, etc.
Framing and Taking the shot:
Because I’m going to use Photoshop for some post-processing, even if my final image is going to be a group of artifacts, I generally shoot one artifact at a time. I do, however, leave room in the frame for the entire group. If you are going to do this, remember to pick one focal length and stick with it for the entire group. No zooming in or out on different artifacts or they won’t be at the same scale. If you are not going to do much, or any, post-processing, or if you want to shoot a group of artifacts in one shot, be sure that shadows cast by one artifact do not encroach on the edge of adjoining artifacts. Also make sure that the background is clean, the scale is straight, and the artifacts are arranged nicely. The goal is to not have any distracting elements that draw the viewer’s attention away from what should be the focus of the image.
All of my photographs get at least some post-processing using Adobe Photoshop CS6. There are many other photo editing programs out there and I assume they all have the same basic editing capabilities that I use in Photoshop. Because I shoot in the RAW format, Photoshop initially opens the image using the Adobe Camera Raw program where I adjust the exposure or white balance if needed and the image is converted to a Photoshop (psd) format. In Photoshop, the first thing I do is copy an image of a five or ten centimeter scale I created in Adobe Illustrator and paste it into my artifact image where it shows up as a separate layer. I then resize the scale image so that it matches the scale in the original photograph. This is purely for aesthetics. The digital version looks much nicer than the scale I created out of foam core. Next I use the “Quick Selection Tool” to select the/an artifact in the image. This tool works quite well, but you must zoom in to make sure all of the edges are selected. When the artifact has been selected I cut it and then paste it back into the image – this makes the artifact its own layer, separate from the background layer. If there are multiple artifacts in the same original image I go back to the background layer, select the next artifact, and cut and paste it to create another layer. At this point the background layer is a mess. It still includes the scale that was in the original photo and now includes a hole, or holes, where the artifacts had been. This mess can be cleaned up in CS6 by selecting the background layer and adjusting the brightness and contrast levels to -100 (be sure the “Use Legacy” box is checked). The result is a clean black background. If I shot one artifact at a time and want to combine artifacts from different images into a group I simply open the second image, select the artifact, copy or cut the selected artifact, and paste it into the original image. Continue this process until you have added all the artifacts you want into the original photo. Because each artifact is its own layer in the image, by selecting the layer you can use the “Move Tool” to move the artifact wherever you want within the image. At this point you can also add labels, arrows, or other text or symbols to the image if desired. I usually add a copyright symbol/logo to images to be used on the web and I save the image as a Photoshop (psd) file in case I want to make more changes later. Finally, I resize the image if needed (depending on how it will be used) and save it as a jpeg.
And that’s it! It may sound complicated, but the whole process usually takes only a minute or two and you are left with an image that looks nice and conveys the intended information.