1. Funded by: © AHDS What happens when you digitise? An introduction to some key themes Alastair Dunning Arts and Humanities Data Service http://ahds.ac.uk/ Think Digital: Best Practices for Digital Resources across the Cultural Heritage Sector

2. Funded by: © AHDS Overview General processes Digital objects Data models

3. Funded by: © AHDS Source  Digitisation  Resource

4. Funded by: © AHDS e.g. William Shakespeare: The Complete Works slidesvideotape John Bright bust © Public Monuments and Sculpture Association sculpture text performance Mark Rylance as Hamlet, Block/TIrmani, June 2000 © Donald Cooper Source  Digitisation  Resource

5. Funded by: © AHDS digital audio/movie recording scan/digital camera/3-D scan/OCR item to digitise digital object Source  Digitisation  Resource

6. Funded by: © AHDS digital resource Title: JOHN BRIGHT Sculptor: Bruce-Joy, Albert Type: Sculpture Date Completed: 1890 Description: marble bust Public Monuments and Sculpture Association collection available through AHDS Visual Arts image catalogue: visualarts.ahds.ac.uk visualarts.ahds.ac.uk Source  Digitisation  Resource

7. Funded by: © AHDS digital resource As you like it, William Shakespeare. Available as DOS ASCII Text (Especially converted for MS- DOS based machines.) Search Results for William Shakespeare http://ota.ahds.ac.uk/ Source  Digitisation  Resource

8. Funded by: © AHDS digital resource September 4, 1995 ITN News At Ten Actress Tilda Swinton becomes a living, sleeping, performance art exhibit for artist Cornelia Parker in an exhibition at London's Serpentine Gallery. Newsfilm Online http://www.bufvc.ac.uk http://www.bufvc.ac.uk Source  Digitisation  Resource

9. Funded by: © AHDS Elements of a digital resource Users Knowledge Experience Culture Environment Hardware Software (OS) (Network) Digital Objects Binary Data Data Models Relationships Users are the most important element Advice on hardware and software, objects and data models can be sought Fit for Purpose: Digital objects must be created with their intended use/purpose of paramount importance

10. Funded by: © AHDS Digital objects Text Image Time-based media

11. Funded by: © AHDS Digital objects - Text Text is data stored as a stream of characters (numbers, letters, etc.) – Text Transcription – OCR

12. Funded by: © AHDS Digital objects - Text Text Transcription Pros: low overhead to start transcription person, keyboard, document hand-written documents can be transcribed transcriber can follow complex disorganised documents Cons: slow and expensive human error © David Leach/Crafts Study Centre 2004

13. Funded by: © AHDS Digital objects - Text Optical Character Recognition Pros: automatic, suitable for digitising large numbers of documents highly accurate for clean, clear type written documents systematic errors can be easy to find and find Cons: current technology is very poor on hand-writing complex document layout can become scrambled 5S5S

14. Funded by: © AHDS Digital objects - Image Images are data understood as a spatial pattern or shape – bitmapped/raster images – vector spatial data

15. Funded by: © AHDS Digital objects - Bitmapped images Bitmapped images are made up of many pixels Each pixel stores information about it’s colour (RGB) Pixels per inch (ppi) dictates amount of visible information The standard archival file format is uncompressed TIFF v6

16. Funded by: © AHDS Fit for Purpose Capture National Gallery Hi-res images 20,000 * 20,000 pixels Old Bailey Online Lower res images 1,024 * 1,024 pixels

17. Funded by: © AHDS Digital objects - Bitmapped images Good practice Check the optical resolution of the scanner Avoid interpolated resolution Capture master images at appropriate resolution and bit depth Check scanning time Record details of scanner/camera settings and any image editing http://www.tasi.ac.uk Scanning versus direct digital capture Always depends on the resource Is there an analogue version of the resource? Time – money – available skills Image quality - colour fidelity

18. Funded by: © AHDS Digital objects - Vector images x,yx,y,z A point represents an exact location in two or three dimensional space Two points define a line A series of connected lines define an area

19. Funded by: © AHDS Digital objects – Time-based media Time-based media – data understood as a sequence through time – audio and video (multimedia)

20. Funded by: © AHDS Digital objects – Time-based media Audio – Moving from analogue to digital called sampling – Frequency of sampling rates Hertz (Hz) –Uncompressed digitisation 36kHz –.WAV and.AIF –MP3 offers good quality compressed (lossy) files

21. Funded by: © AHDS Digital objects – Time-based media Video – Issue of file sizes and bandwidth – MPEG - The Motion Pictures Experts Group standards are the most popular compression standards –The three standards, MPEG-1, MPEG-2, MPEG-4 –Compression basically works by selecting key frames and only recording changes between the frames (but it gets a lot more complicated!)

22. Funded by: © AHDS Data models List, one item follows another Tree, each item can have several children Sets, items belong to one or more groups Geography/geometry, items are located using a co-ordinate system

23. Funded by: © AHDS Lists e.g. spreadsheet

24. Funded by: © AHDS Trees and hierarchies e.g. Text mark-up

25. Funded by: © AHDS Sets e.g. Relational database Table: art_work Id no. Artist Title Description Subject Material Table: image Id no. File name Creator Date Size (pixels) Resolution Orientation one to many relationship, avoids redundancy, i.e. art work information is stored only once

26. Funded by: © AHDS Geography/geometry GIS (spatial) database The distribution of things upon the surface of the earth Maps and plans - Aerial photographs - Co-ordinate lists Figure created by Peter Halls using data from the Cottam Project directed by Julian Richards. Image copyright © Archaeology Data Service.

27. Funded by: © AHDS Selecting your Data Model Consider how the original source material is organised What your users are familiar with Fit for purpose Seek specialist advice

28. Funded by: © AHDS Selecting software 1 Avoid little-used software with proprietary features Select software that can perform the right tasks – e.g. Don’t use a word processor as a spreadsheet – e.g. Don’t use a webpage editor as a database Watch out for licencing costs

29. Funded by: © AHDS Selecting software 2 Do look for software with export and import options. Do look for software that supports important standards. e.g. How data is organisedData model Important standards trees mark-upXML (SGML) sets relational databases SQL coordinates CAD or GIS DXF, ESRI shape files

30. Funded by: © AHDS Summary A discussion of general processes including: –Source –Digitisation –Resource A brief overview of digital objects including: –Text –Image –Time-based media A look at data models and selecting software.