Introduction
Records Management
The Digitization Handbook provides detailed instructions on the digitization of approved University records. The Handbook helps meet requirements defined in the "Electronic Records as Documentary Evidence" standard published by the Canadian General Standards Board (CAN/CGSB-72.34-2017). See the Records Management website for more information about the University Records Management program.
Introduction to digitization
Digitization is the process of creating digital representations of analog media. Libraries staff use specialized equipment to carry out the analog-to-digital conversion of documents, books, photographs, recordings, and other formats. Staff also work with approved vendors to digitize audiovisual material. This work produces digital master copies of these resources for long-term digital preservation. Staff also use software to create access copies
The University Archives maintains a small collection of technical manuals and other resources to support digitization training activities, project planning, and self-directed learning.
Digitization guiding principles
The following principles guide digitization activities:
- Do not harm the original material.
- Retain analog material after digitization.
- Digitization supports open access to analog archival and library material, whenever possible.
- Digitization produces high quality uncompressed digital master copies of analog material to support long-term digital preservation.
- Digital master copies are free of artifacts introduced by the digitization process, whenever possible.
- Digital photography workflows require lighting equipment that produces 5500 K light (see colour temperature).
- Digitization produces high-quality digital access copies of analog material.
- Copyright assessments are performed before disseminating access copies. Copyright assessments are documented using the Copyright Assessment Worksheet.
- Digital objects produced during digitization are named and organized in accordance with the reference codes or other unique identifiers assigned to the analog material (see Appendix B - Guiding principles for file naming and file organization).
- Digitization projects employ metadata standards and best practices that allow digital objects to be findable, accessible, interoperable, and reusable (see Wilkinson et al, 2016).
- Implement quality control measures throughout the digitization workflow.
Note: These principles have been adapted from the Principles and Specifications of the Library of Congress’ Preservation Digital Reformatting Program: http://www.loc.gov/preservation/about/prd/presdig/presprinciple.html.
Technical specifications for digitization projects
Digitization projects require clearly established technical specifications:
- Image resolution – refers to the detail an image holds. Higher resolution means more detail.
- Bit-depth – the number of bits used to represent each pixel in an image.
- Master copy – the uncompressed high resolution image created to support long-term preservation
- Access copy – compressed medium/low resolution file created to support access
Other technical specifications for digital images include settings for brightness, contrast, and saturation.
Certain material require further technical specifications. For example:
- Audiovisual material requires attention to additional technical specifications, including sampling rate, codecs and file formats, and aspect ratio. See Appendix C - Technical specifications for "master" files for more guidance.
- Material that must be digitized with digital photography equiipment requires attention to lighting and additional technical specifications, including ISO, shutter speed, aperture, white balance, and metering method.
Compression methods
The process of creating access copies involves image compression. There are several points during the workflow where compression settings can be configured:
| Compression methods | Description | When is the Option Available | Further reading |
|---|---|---|---|
| TIFF to JPEG conversion | Batch convert master TIFF files to JPEGs. Image reduction depends on "Resize to fit" and "JPEG quality" settings. Default is normally JPEG quality of 12 (i.e., maximum quality) and no resizing. | During batch conversion from TIFF to JPEG | |
| "Resize to fit" | Batch resize images to a standard width or height. This reduces the overall size (i.e., dimensions) of the image. Can be applied during or after TIFF to JPEG conversion. | During batch conversion from TIFF to JPEG | |
| JPEG quality scale | Adobe Photoshop uses a JPEG quality scale of 0-12. Can be applied during or after TIFF to JPEG conversion. | During batch conversion from TIFF to JPEG | An analysis of Lightroom JPEG quality export settings (Jeffrey Friedl's blog) |
| Save small, medium, large PDF | Adobe Acrobat Pro provides the option to save PDFs as small, medium, or large files. This option has no perceptible impact on image quality or file size. | Compile a PDF from multiple files | |
| Downsample during OCR | Downsampling reduces the number of pixels in an image but does not reduce the overall size (i.e, dimensions) of the image. Adobe Acrobat Pro provides the option to downsample to 600 dpi or 300 dpi when recognizing text in a PDF. | Recognize text in a PDF |
Access copies
Access copies are disseminated via discovery platforms and also backed up on the Libraries' storage server. Intermediary JPEGs used to produce PDF/A files do not need to be preserved.
Use the following table to determine the appropriate "access copy" format and identify the necessary tools and instructions:
| Analog Format | Digital access copy format | Tools | Instructions |
|---|---|---|---|
| Text | PDF/A scanned with OCR software | Adobe Photoshop, Adobe Bridge, Adobe Acrobat Pro, ABBYY FineReader | 2.3 - Create access copy PDF/A files |
| Graphic material | JPEG | Adobe Photoshop, Adobe Bridge | 4.3 - Create access copy JPEGs |
| Herbarium specimen | JPEG | Adobe Photoshop, Adobe Bridge | 16.2 - Create digital "master files" and access copy JPEGs of herbarium specimens |
| Moving images | MPEG-4 | Sony Vegas | Coming soon. |
| Sound recordings | mp3 | Audacity or Sony Sound Forge Pro | Coming soon. |
Quality control
Quality control is extremely important during the process of creating digital masters, because:
- Digital master files become the definitive source for access copies and other derivative files.
- Digital master files help ensure the analogue original will not need to be digitized again. This helps avoid exposing archival material to harm.
- Digital master files help ensure the content looks as good as possible as technology continues to advance.
- Digital master files may become the true master if the analogue material deteriorates or becomes unplayable.
See Appendix A for further guidance on quality control.