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Digital Commonwealth is a Web portal and fee-based repository service for online cultural heritage materials held by Massachusetts libraries, museums, historical societies, and archives. The portal facilitates the searching and browsing of member institutions' digital assets, allowing the discovery of all kinds of digital resources including manuscripts, images, historical documents, and sound recordings. The repository provides a storage service for institutions that choose not to host their own digital assets. The metadata stored in the repository will be indexed by the portal.
Building a digital collection to be accessed via the portal requires thoughtful planning. What follows is a list of steps to be considered when planning a digital project.
Why digitize? There are numerous reasons:
Please note: digitization is an access tool, not a preservation method. For more information about preservation and sustainability issues relating to digital assets, see section 7 "Preserving Digital Assets" below.
Some questions to address:
Once your institution has selected the items or collections to digitize, document the decision-making process -- the rationale for what was chosen, staff involved in the process, the date -- as this may inform future selection strategies.
Organizing materials according to their provenance and original order protects their context and achieves physical or intellectual control over them. Describing the item or collection(s) facilitates access and creates a record of the organized collection(s) and its components. These descriptive tools (finding aids, inventory lists, catalog records) often include container lists and notes about the title, size, dates, and scope and content of the collection.
A well-organized and described collection enhances access to the materials, increases its value, and facilitates the selection process for digitization.
Selecting an appropriate approach to digitization is at least as important as selecting the items or collections to digitize. Although good-quality, low-cost scanners are widely available, creating digital images on a readily available desktop scanner is not the only option; in fact, using a reputable contractor, rather than digitizing in-house, might be a better choice. To create digital images of maximum utility to the user requires knowledge of image specifications, scanner hardware capabilities, software configurations, image quality control issues, and the ability to create appropriate and complete metadata. It is possible to create what appears to be an adequate digital image, but sometimes even large digital images (with what appear to be appropriate pixel dimensions) might not be usable if they do not have good tonal range and color balance. Either way, digitizing in-house or working with a vendor, establishing digital image specifications beforehand ensures quality and functionality of the end product.
Please note: When the Digital Commonwealth's repository service policy has been finalized, the recommended specifications will be stated here.
The Northeast MA Regional Library System's digital repository uses the following digitization specifications:
| Scan Size (ratio) of Original Item: | 1:1 ratio |
| Resolution Bit-Depth | Color Photographs: 24 bit Black & White Photographs: 8 bit gray scale Black & White Text: 1 bit Resolution |
| Resolution DPI | Digital Master: 600dpi Access Image (for printing or detailed web viewing view): 300dpi Web Viewing: 72dpi |
| Image File Formats | Digital Master: Uncompressed TIFF Web Images: JPEG Access Image (for printing or detailed web viewing): JPEG |
For another example of digitization specifications, visit C/W MARS' Digital Treasures: http://dlib.cwmars.org/cdm4/images/cwmars_benchmarking.pdf
| Working with a vendor | Digitizing in-house | |
| Project management | Locate a suitable vendor and develop a project agreement (scope; cost; technical specifications; shipping, storage, security, and handling requirements; and project schedule.) The vendor is responsible for meeting all contractual obligations. | Determine the project schedule and staffing, including project supervision. Internal staff must coordinate and complete all tasks on time and meet required technical specifications. |
| Funding | Have sufficient funds to pay the vendor. | Have sufficient and reliable funding over time to cover staff, equipment, supplies, and maintenance costs. |
| Staff expertise | Maintain ongoing communication with the vendor to ensure compliance with technical specifications. The vendor is responsible for having knowledgeable staff. | Have production staff who can create digital images according to technical specifications, and supervisory staff who can manage digitization projects. |
| Technological capacity | Vendor maintains up-to-date hardware, software, and network infrastructure needed to meet all contractual obligations. (Note: your institution needs a mechanism to ensure quality control. This may require some equipment for staff to review images prior to paying the vendor.) | Buy, configure and maintain hardware, software and network infrastructure needed to create all necessary digital products. Responsible for quality control, including review of digital images. |
| Materials handling | If imaging is done offsite (sometimes vendors work onsite), the vendor is contractually responsible for secure and appropriate storage and handling of materials, and for packaging and return shipping. | Handle materials appropriately during digitization. |
| Hardware / software / obsolescence | Vendor ensures its hardware and software is up to date. | Maintain up-to-date hardware and software. |
| Digital storage / sustainablity / preservation plan | Vendor is responsible for adequately storing the digital files during the time of the contract. Institution must ensure file maintenance, data migration, sustained access to, and preservation of digital assets after completion of the project. | Responsible for a sufficient backup system for all digital files during image production and beyond. In addition to backup systems, create a digital preservation plan that should include data migration, file integrity checking, continued functionality, refreshing and reformatting the data. |
| Metadata | Vendor will provide metadata as per the contract. | Responsible for descriptive, administrative, and structural metadata. |
After they are created, digital assets are stored on a host server, either within the home institution or within a repository service. To be accessible, these digital assets require metadata, which is information about or pertaining to the digital assets (object type, size, date, creator, subject, provenance, etc.). Metadata facilitates data management, enables access, and enhances sustainability. The more complete the metadata, the easier it is to manage the digital assets.
Metadata typically fall into several categories, including administrative, descriptive, preservation and structural. Dublin Core (www.dublincore.org) is an important descriptive metadata standard that allows for the discovery of digital assets. The full Dublin Core standard includes fifteen elements or fields which are listed below. Recommended best practice is to use a content standard, thesaurus, or encoding scheme for each element. The elements in bold are particularly useful for the retrieval of digital assets by the Digital Commonwealth.
For the portal to provide access to digital assets from multiple repositories, it must harvest (or gather) Dublin Core metadata related to those assets in a predictable and structured manner. An international standard known as the Open Archives Initiative (OAI) (www.openarchives.org) uses Dublin Core elements and defines the requirements for making descriptive metadata harvestable. The portal requires compliance with the OAI standard.
Making digital assets available on the Web can be accomplished in more than one way:
Options include:
In either case, costs will be associated with storage of the records.
Please be aware that if the project is outsourced and the vendor is able to provide an affordable repository for your digital assets, they may not be searchable in the Digital Commonwealth portal unless the vendor is a member.
Members of the Digital Commonwealth contribute OAI-harvestable metadata to the portal in a variety of ways depending on where their digital assets are stored.
If the digital assets are stored in:
Digitization is a way to provide access to cultural materials that are fragile or rare by the creation of a digital surrogate; but digital resources must also be preserved. Some of the preservation issues to be aware of in the long-term sustainability of digital objects are:
Check with the repository service provider regarding their policies on preservation of digital assets. General guidance on preservation issues, including resource links, is provided at www.digitalcommonwealth.org/docs/preservation/.
Making collections searchable and available on the Web may generate new attention for an institution. A whole new audience can discover collections, and some will want to visit in person. Research shows that if you build it, they will come!
Northeast Massachusetts Regional Library System, Digitization Checklist http://www.nmrls.org/nmdl/digichecklist.htm
Northeast Document Conservation Center, Preservation Leaflets http://www.nedcc.org/resources/leaflets.list.php