DISA Guidelines for Best Practice. No 2. Digital conversion of text, photographs and archival material

Transcription

1 DISA Guidelines for Best Practice. No 2 Digital conversion of text, photographs and archival material Created: 20/10/2005 Last Modified: 03/10/2007 1

2 Table of Contents 1. File naming conventions p.4 2. Digital conversion p Image capture 2.2 Image specifications Books and journals Archival materials Photographs 3. Derivatives p Books and journals 3.2 Archival material 3.3 Photographs Black and white photographs Colour photographs 3.4 Automated generation of web-ready gifs 3.5 PDF creation 4. Compression and transfer p Data integrity 4.2 Compression 4.3 Data transfer 4.4 Quality control 2

3 Introduction The main purpose of these Guidelines for Best Practice is to document the digital conversion standards and file naming conventions applied in the digitisation of various media at partner institutions. Whilst these guidelines encompass the minimum requirements to be met in image capture, additional guidelines will be made available for best practise in indexing, web presentation, storage and digital preservation. Please consult the DISA website for additional guidelines. Digital collections are by nature heterogeneous in content, and therefore no one specific parameter can be applied to all objects. These guidelines have been developed for:- Increased interoperability and accessibility across institutions through the use of generally accepted international standards and formats. Consistency in quality. Promotion of best practices thus avoiding future rescanning of material. Technology is constantly changing in this field and therefore this document is likely to be updated from time to time to reflect these changes. Please feel free to comment and make suggestions to support this dynamic process. Scope of the Guidelines These guidelines are not intended to serve as a detailed manual on practical issues of scanning, or the use of various software packages. Separate training opportunities are provided by the DISA project as required. 3

4 1. File naming conventions Please consult the DISA Guidelines for Best Practice. No 1: File naming conventions before embarking on digital capture. 2. Recommendations for digital conversion 2.1 Digital Capture Create a document folder using the correct file naming convention, outlined in Section 1 above. Create two subfolders in document folder named image and text. No caps, all small letters. Save tiffs to image Save OCR text files to text. See Section 3 below 2.2 Image specifications Books and journals Front covers with colour 600dpi 24-bit RGB colour at 50% of pixel width, resampled to 8-bit paletted Front covers with no colour 600dpi 8-bit grayscale at 50% of pixel width Individual pages: 600dpi 8-bit greyscale at 50% of pixel width Archival material (diaries, letters, manuscripts, memorandums etc) All archival material except photographs: 600dpi 8-bit greyscale at 100% of pixel width Photographs Archival colour photographs: 600dpi RGB (24bit) at 50% of pixel width. Photographs on book and journal pages: 200dpi greyscale (8bit) with pixel width reduced to 500 pixels. Archival black and white photographs: 600dpi grayscale (8bit) at 100% of pixel width Enhancements Images must be free from bleed through of reverse text and of gutter shade as far as possible. 4

5 Images must be straightened horizontally. Any marks integral to the original document, annotations, watermarks, etc. should not be removed. 3. Derivatives of Images 3.1 Books and journals Two derivatives of all page images are generated. They are 700 and 800 pixels wide and are.gif images They are named according to the file naming convention outlined in DISA Guidelines for Best Practice. No 1: File naming conventions For example: dev1n274bkcvr1 Add 700 or 800 to the name and save as a.gif Thus dev1n274bkcvr1-700.gif dev1n274bkcvr1-800.gif 3.2 Archival material Two derivatives of all archival material images are generated. They are named according to the file naming convention in Section 1 above, e.g. rep p001 Add 700 or 800 to the name and save as a.gif Thus rep gif rep gif 3.3 Photographs Black and white photographs One derivative of black and white photographs is created as 200dpi, 8-bit greyscale, at 500 pixels wide and saved as a jpg file. These files are named exactly as the.tif image but with a.jpg extension, eg: pho jpg Colour photographs One derivative of colour photographs is created as 200dpi 8-bit paletted colour, 500 pixels wide and saved as a jpg file. These files are named exactly as the.tif image but with a.jpg extension, eg: pho jpg 5

6 3.4 Automated generation of web-ready gifs Request the necessary script from the DISA office Open Corel Photo Paint or equivalent graphics software Click Tools=> Corel Script => Run Script Run script for gif creation from default directory to which it is saved: ie: [My Documents] \webready.csc Direct the script to your image directory containing tiffs. Accept default 700 and 800 pixel widths. The script will create a subdirectory called web-ready inside image, in which it deposits the.gif files. 3.5 PDF creation Open Adobe Acrobat or equivalent PDF writer Click Create PDF Button Choose From Multiple Files,,. Browse to web-ready folder Choose only the 800dpi GIFs Make sure all check boxes are un-ticked Save PDF to the document folder, using folder name, eg: rep pdf Open PDF and check page sequence. Use PDF to QC images. 3.6 Optical Character Recognition (OCR) Open ScanSoft Omnipage or equivalent OCR software Open tiffs in Omnipage and perform OCR on selected tiffs. Correct only personal names and place names. Save twice to text subfolder in relevant document folder: i. Save with Page Range=All pages and File options=create a new file for each image file. This will automatically save individual text files with their associated tiff filenames. ii : Save a second time with Page Range=All pages and File options=create one file for all pages. Save to text subfolder in relevant document folder, using folder name, eg: rep txt 4. Compression and transfer 4.1 Data integrity When writing large image files to CD/DVD or external HDD for transfer, check for data integrity, i.e. corruption of files caused by power dips and intermittent loss of network connectivity. To compare source and destination folders, run the CDCheck utility. 6

7 4.2 Compression Compression of large file sizes is essential for transfer and storage. Select a nonproprietary lossless data compression program, which has an excellent compression ratio, viz; BZip2 or demo version of WinRAR, or WinZip. 4.3 Transfer of completed production Unless by regular prior arrangement, notify DISA of file transfer readiness, and you will be informed date on which courier collection will occur. Pack media firmly and cushion with bubble wrap for transfer. Include a copy of the workflow spreadsheet with submission to reflect content of submission. 4.4 Quality control Incomplete or incorrect files will be returned from DISA, by courier, within 7 working days. 7