IR Workshop Digitisation 1-3 April 2009 Presented by Henning van Aswegen

DIGITISATION - ? “Digitization is the process of converting information into a digital format. In this format, information is organized into discrete units of data (called bits) that can be separately addressed (usually in multiple-bit groups called bytes). This is the binary data that computers and many devices with computing capacity (such as digital cameras and digital hearing aids) can process.” (whatis.com)whatis.com

HISTORY OF INFORMATION

PURPOSE Why do we need to digitise: For access or preservation?  Preservation through access  “The primary use of digital imaging into the near future will be to improve access” - Anne R. Kenney (1998) Alternative preservation methods  “Microfilm possesses two simple advantages over most other media used for recording information: it is long-lived and it is readable by humans” - Suzanne Cates Dodson (2001)Suzanne Cates Dodson

ABRIDGED LIFE CYCLE OF DIGITISATION MATERIALS PROCESSES PRODUCT PLANNING

MATERIALS

GUIDELINES Dependant on the purpose of any given institutional repositry Examples of existing and published guidelines:  Selecting library and archive collections for digital reformatting (RLG, 1996)  Digital Imaging Best Practices Version 2.0 (BCR's CDP, 2008)BCR's CDP, 2008 Example of an existing institutional guideline:  Selection criteria for digital reformatting (National Library of Medicine, 2008)National Library of Medicine, 2008

MATERIAL SELECTION Questions to ponder: Who owns the rights to the original? Does its nature warant digitisation? What is the physical condition of the original? Where will it be done? Who are the current and the potential users of the original? What are the costs and benefits of digitisation? Know your originals Know your purpose

KNOW YOUR ORIGINALS Format of the original  Printed text, photographic material, audio, video, etc? Condition of the original:  Automated processes, conservation required? Size of the original:  Similarly sized originals smooth workflow Colour content of the original:  Colour scanning more expensive and time intensive

IN-HOUSE OR OUTSOURCE In-house Pros:  Experience  Control  Adjustment Cons:  Large investment  Time intensive  Limited production Outsource Pros:  Lower cost  Less risk  High production Cons:  Less control  Complex contracts  Lack of knowledge

KNOW YOUR PURPOSE Cost:  Hardware  Staff  Maintenance Benefits:  Increased visibility  Ease of access

STANDARD WORKFLOW MATERIALS Select your materials Apply preservation where needed Use caution where needed Send it away for digitisation

STANDARD WORKFLOW Digitise the selected item Use automated processes where possible Manipulate the file to produce different versions Ensure digital content survival and accuracy PROCESS

STANDARD WORKFLOW One digital master, highest possible resolution, Tiff format accepted as standard Derivative images for access purposes PRODUCT

TECHNICAL OVERVIEW

DIGITAL IMAGE TYPES Raster image Vector graphic

RESOLUTION DPI and PPI Expressed as dots per inch (DPI) – archeaic term, prefered term for output to printed media - or pixels per inch (PPI) – proper term, prefered for actual image. Refers to the density of information contained in an electronic image file.

BIT-DEPTH Relates to the level of colour that will be captured. Attached to each individual pixel. Represents the tonal value of the pixel. 1-bit image has only black and white (1 bit) 8-bit image has 256 shades of grey (2^8 = 256 shades) 24-bit image has millions of shades of colour (2^24 = 16,777,216 shades)

COLOUR BITONAL GRAYSCALE RGB Additive colour system CMYK – Printer Colour Subtractive colour system

FILE FORMATS JPEG Joint Photographic Experts group TIFF Tagged Image File Format GIF Graphic Interchange format Bitmap SVG Scalable vector graphics MP3 Mpeg 3 audio encoding WMA Windows media audio file PDF Portable document format Audio video Interleaved DOC Microsoft Office Word format Format description of the Library of Congress Global Digital Format Registry BMP AVI

COMPRESSION ALGORITHMS Lossless compression  No information lost  Suitable for digital master  Examples:  TIFF Lossy compression  Information is lost  Suitable for access version  Examples  JPEG and MPEG

RECOGNISED STANDARDS WORLD DIGITAL LIBRARY DIGITAL IMAGE STANDARDS ORIGINALCOLOURFORMATRESOLUTION TEXTUAL: Text and text with grayscale illustration GrayscaleTIFF300 DPI TEXTUAL: Text with colour illustration ColourTIFF300 DPI TEXTUAL: Papers and periodicals Grayscale/Colour – Depends on original TIFF300 DPI Pictorial: Images, eg photographs Grayscale/Colour – Depends on original TIFF 300 DPI/600 DPI if smaller than 125 cm2 Cartographic: Maps and atlases ColourTIFF300 DPI

SCANNERS Flatbed scanner Overhead scanner Handheld 3d scanner Document feed scanner Large format (A1) scanner Film scanner

HARDWARE Large scale graphics processing At least one powerfull workstation At least one large backup server

RECOMMENDATIONS Scanner determined by collection As much hardrive storage as possible High end desktop graphics cards As much memory (RAM) as possible Mid level processor

EXISTING DIGITISATION PROJECTS AND INSTITUTIONAL REPOSITORIES Michigan Digitization Project Australian digitisation projects Europeana Minnesota Digital Library World Digital Library Oxford Digital Library Native American Constitution and Law Digitization Project

CONCLUSION Digitisation is a tool not a goal

SOURCES AND ADDITIONAL READING UKOLN World Digital Library BCR Ask a geek