Characteristics of photographs Multiple versions possible Negative and the print and copy photography Colour and monotones – fidelity is vital May be fragile, dirty and even combustible May be flexible or rigid, mounted or in strips (e.g. albums, slides, negative strips) Will probably need special handling Will benefit from specialist equipment
Capture methods for visual artefacts and photographs Digital Imaging digital cameras (as for manuscripts) Scanning flatbed scanners – primarily for prints and plates drum scanners – primarily for transparencies film scanners – specialist high end products slide scanners – slides and transparencies
Handling Every single interaction with a fragile original can compromise it Many of these may be hundreds of years old … … we want them to last for hundreds more years So special handling is crucial
Handling Conservation practice in human handling Heat levels – most critical due to build up Light levels Dust-free environment
Image Quality How do we know if it is good enough? Visual sharpness Laterally reversed images Dirt Skew Image completeness Guidance available from the RLG Publications by Franziska Frey (Rochester Institute of Technology)
Case Study: CVMA Corpus Vitrearum Medii Aevi – medieval stained glass The content is only renderable from photographs of the subject. Comprehensive database with high levels of descriptive metadata. Further additions will include maps and church plans linked to window images.
Specifications of CVMA Digitisation Source: 35mm slides, medium & large format transparencies, photographic prints Scanning dpi: 35mm – 2,700 dpi Medium format – 1,200 dpi Large format – 1,000 dpi Print – 600 dpi All 24-bit RGB colour File formats: TIFF master (uncompressed) JPEG for web Courtesy of CVMA Project, Courtauld Institute of Art
Case Study: Shetland Isles Museum Glass plate collection - >80,000 items In-house scanning using flatbed scanners 600 dpi, 8-bit greyscale specification Delivered on the web with the option to buy content. Online images are thus relatively small.
Large format originals Maps Drawings Technical drawings – engineering or architectural Very hard to scan – photographic surrogate is often the best method Accurately representing scale is difficult Representing this content online is difficult
Digitization options for 3-D objects What do we mean by 3-D objects? Anything! Sculpture Public monuments Machinery Archaeological artefacts Buildings Books
Digitization options for 3-D objects What are the options? 2-D photography in single shots 2-D photography in multiple shots resultant images stitched into a 3-D rendition using Quicktime Video Use of programs such as Macromedia Shockwave to create 3-D Virtual Reality