It is critical that archaeologists create the best possible image archive for future generations. The archaeologist as photographer knows what artifact detail or site viewpoints should be recorded for posterity. Archaeologists are required to develop good skills in photography as commercial photographers would rarely be employed for this type of photodocumentation. The resulting images should be correctly exposed and focused, suitably lit, and free of distortion with attention paid to accurate color representation. To indicate size it is essential to use a contrasting metric scale, a human figure, or the insertion of a hand. Photographic backgrounds, scales, and other information must not compete with the subject for attention. Documenting artifacts for museum publications, exhibitions, or public lectures may require some interpretative approach.
The archaeological photographer is often challenged by heat, moisture, cold, wind, dust, terrain, vegetation, and the pressure of rescue archaeology with limited time. Dealing with high contrast on a site in bright sunlight and achieving contrast in a wet trench are other challenges. The archaeological photographer must apply different composition and lighting methods to a wide variety of artifact types and composite materials such as pottery, coins, glass, bone, metal, stone, wood, and textiles. Aerial photography and satellite imagery are extremely useful recording, prospection, and analytical tools for the archaeologist. Low-level aerial archaeology platforms such as kite aerial photography, balloon photography, and photographic booms are constructed by specialists to obtain aesthetic vertical and oblique site images that are also useful when creating large-scale photo mosaics, site plans, and three-dimensional topographic models.
Scientific photographers employ infrared, ultraviolet, and multispectral imaging techniques to highlight detail in ancient textiles, painted wood, canvas, leather, and the ink on parchment such as revealed on the Dead Sea scrolls. Fluorescence photography can distinguish the presence of organic and mineral elements on wall paintings and textiles and xeroradiography can assist conservators in the restoration of metal artifacts. Archaeologists exploring tombs or confined spaces utilize endoscopic photography and optical fiber technology. Photomicrography and scanning electron microscopy are tools for archaeologists to analyze animal and plant residues. Stereoscopic imagery can bring out variations in texture or technological construction in features or artifacts. Although video has not figured prominently in methodical archaeological imaging, it has played a large role in recording celebrity archaeologists and objects for popular television documentaries. Maritime archaeologists use either purpose-built underwater camera systems with electronic flashes or housings for land cameras.
The greatest change in archaeological photography is the development of digital imaging. It is critical that digital cameras and other devices provide high-quality archival records. The use of large format or medium format cameras with digital backs is still the ideal in archaeology because of the level of detail and image enlargement obtainable from the negative or file. However, most archaeological photographers tend to use 35-mm SLR and digital SLR equipment because of the expense of the larger formats and for ease of handling on site. Macro lenses are a must for artifact photography and additional equipment is required to replicate studio conditions in the field.
Digital imaging offers the potential to speed up the documentation of endangered sites due to development, weather, and war. The digital images can be processed anywhere for virtual exhibitions and archives. The development of close-range three-dimensional laser scanning allows archaeologists to create virtual monuments, record ancient interiors, and illustrate sites using “fly-through” movies. Photogrammetric cameras and software can be used to survey panels of rock art or document heritage buildings. Photomodeler software provides a photo-realistic, three-dimensional model of the ship, artifact, building, or site by measuring from and incorporating the original photographs. High-resolution document scanners can be used to record low-profile artifacts such as ceramic shards, glass beads, and bone. Archaeologists use image registration software to rejoin mosaics, architectural columns, and pottery from scanned or photographed fragments. Digital image processing has shed light on difficult-to-detect rock art images, providing the archaeologist with a new dating tool and a potentially vast corpus of art.
As in many other disciplines, digital imaging has provided greater opportunities for archaeologists to store, retrieve, and disseminate research images over the Internet, via image databases, or on optical media. Low-cost CD/DVD burners, USB ports, memory cards, card readers, and wireless technology make duplicating and image transfer between field, laboratory, or office easy. The challenge is to ensure authenticity of the original digital image when manipulation of the image may affect research outcomes. Image duplication and preservation must be carefully considered in the future as file formats change. The RAW file format will emerge as the glass plate negative of old, but it is not yet standard among camera manufacturers. Digital asset management software such as Fotostation, Extensis Portfolio, and Cumulus are efficient tools to manage archaeological image workflows. Adobe PhotoShop software can be used to create composite illustrations by combining photographs, vector, and raster information.
Archaeological photographers need to be comfortable with digital imaging technology. World wide, countless archeological images will be uploaded to image servers to provide comparative artifact typologies and site analysis. Knowledge of color management software, digital asset management, file workflows, and format conversion will become critical for maintaining the integrity of images. Archaeologists now provide daily posting of digital images or real-time video to project Web sites. Archaeologists in the field are also able to process images faster by wireless technology and developing mobile phone technology will provide immediate feedback for isolated survey teams. Some digital SLR models provide global positioning satellite (GPS) connectivity to enable spatial EXIF data to feed into geographic information systems (GIS) databases. Hand-held three-dimensional laser scanning cameras may be eventually developed, with instrument software to provide three-dimensional “point clouds” corresponding with texture from photographic frames. Unmanned aerial vehicles (UAVs) will be used by archaeologists in the future to undertake low-level aerial archaeology projects as well.
Archaeological photography has been revolutionized by digital imaging and further convergence of the technology will lead to innovative applications in the field and laboratory. However, archaeologists today still rely on the glass negatives and prints from the past, which have stood the test of time. Whatever the technology, the challenge for archaeological photographers is to provide a permanent archive of our cultural heritage that is equal to or surpasses the photographic standards of the past."
Fotografia: Ricardo Soares & Sara Navarro