The use of digital technologies has opened up access to the primary sources that are fundamental to humanities scholars. Whether this is through straightforward digital photography, audio capture of oral histories, or more advanced techniques that give access to three-dimensional objects and landscapes, the ability to understand sources in detail without needing access to original artefacts has enabled new research and democratised fields of study.
As these technologies develop, new methods have been developed of enhancing and displaying features of artefacts that have been otherwise hidden. Techniques such as RTI allow the enhancement of surface structure, making worn and difficult inscriptions more readable. 3D scanning and photogrammetry have allowed the analysis of object use, and enable us to print 3D surrogates that can be handled and explored. And methods such as multi-spectral imaging reveal new secrets such as the composition of pigments and inks, and the ability to isolate textual features.
Underlying this is a methodical and scientific approach to imaging that aims to preserve and protect the original sources, that is gathered under the umbrella of Digital Humanities. Many of these methods are new to humanities study, though they have been prevalent in other disciplines for some time. The application of digital methods to the study of human cultures, languages and arts remains an exciting field of development.
The capture of manuscripts and visual material through digital photography has revolutionised access and study in a number fields. Photography can give access to rare and fragile manuscripts, can help to ensure that knowledge is not lost when physical objects are prone to decay or damage, and can reveal new information with modern techniques such as multi-spectral photography, X-rays and microscopy.
The large-scale digitisation of documents presents its own problems, and projects to create digital resources must consider issues of workflow, storage, sustainability, cataloguing and metadata creation and ultimately the sustainability of the digital objects in the long term. Understanding the nature of the physical object being photographed can also be critical in order to obtain the best results with least damage to originals.
A fundamental question in the imaging of artefacts for research arises around the effectiveness of the digital surrogate (copy) to represent the original. The introduction of scientific methodology, which provides some reproducibility in the creation of surrogates, has led to a more effective analysis of what can be measured or understood from a digital surrogate, and what needs to be referred back to the original. Techniques such as colour management and multi-spectral analysis can give some objective certainty that aspects of the surrogate are extremely similar to the original.
Audio recording has been used for historical and cultural purposes since the inception of audio capture technologies such as wax cylinders and gramophones, and it can still be an economic and immediate medium to record research and to disseminate results and interpretations.
A particularly rich area of resources and methods is in Oral History, with a number of guides to best practice available:
Digital objects are often created to assist in the preservation of artifacts, providing non-destructive means of access for fragile objects, or detailed records of their condition or physical properties. But digital objects, whether images, text, or 3D representations, must be carefully considered and cared for. The management of digital assets can be just as involved as that for physical artifacts. Formats, metadata, storage and archiving must all be taken into account.
There are a number of widely used techniques for creating 3-dimensional representations of objects. Each places emphasis on a different aspect of the representation, whether this is the visual effect, the accurate capture of colour or shape, the enhancement of certain features, or the creation of 3D surrogates through use of 3D printing.
Photogrammetry has developed from techniques of stereoscopy and structure from motion to become a general-purpose tool to capture and create objects and landscapes. It takes still images of a scene from viewpoints all around a given subject, and using the embedded metadata and other information in the images, recreates the structure and surface colour of the subject. It can produce highly accurate results if the process of taking images is carefully controlled.
Structured Light Scanning allows a more interactive process of creating a 3D surrogate. The scanner throws a pattern of light across an object, and uses sensors to read the reflected pattern, discerning the surface shape from this in real time. On some models of scanner, cameras capture colour information in addition, to create a wire frame model with an overlay or skin of texture and colour.
Laser Scanning provides a means to capture large structures, such as archaeological sites or buildings. The scanner is placed at appropriate locations around the site, and the structure of the scene is calculated from the time-of-flight of a laser beam cast around the scanner. Placement of the scanner is crucial, and usually multiple captured scenes are merged to create a full view of the site.
Reflectance Transformation Imaging is a method for extracting 3-dimensional surface data from a single viewpoint. By varying the lighting angles in a controlled manner, it creates a matrix of surface 'normals' that indicate the direction of reflected light from the surface.This representation of the surface can be enhanced mathematically to exaggerate the surface relief, and can produce views of marks, inscriptions and indentations on surfaces to assist in reading or for scientific understanding, e.g. butchery marks on bones or tool marks on bindings.