University of Minnesota Digital Conservancy: Digital Imaging Guidelines

	Home

Browse
	collections
	authors
	titles
	subjects

about
policies
f.a.q.
contact

best practices
guide to submitting your work

login to:
	submit your work (authorized users) new user?

University of Minnesota Digital Conservancy >

Digital Imaging Guidelines

Introduction

Digital photography, whether analog to digital conversion or born digital, has been identified by the University Digital Conservancy for inclusion in its institutional repository. The recommendations set forth in this document reflect current best practices and standards in the field of digital imaging. Departments, faculty and staff wishing preserve their image files with the University Digital Conservancy are strongly encouraged to review and implement these guidelines.

Image Quality

Images should be saved in a file format that best ensures the stability and long-term preservation of the object. To that end, the University Digital Conservancy recommends that, whenever possible, all image file formats be both non-proprietary/open source and uncompressed.

To date, the TIFF (Tagged Image File Format) is the most often used file format for saving high quality digital images. The UDC will also accept other image file formats as well, including TIFF (compressed) JPEG, and GIF, though support levels for these files may be lower.

Recommendations by Source

Text
File Format	TIFF (uncompressed)
Bit Depth	1 bit bitonal 8 bit grayscale 24 bit RGB color
Spatial Resolution	600 ppi
Spatial Dimensions	100% of original

Photographs
File Format	TIFF (uncompressed)
Bit Depth	8 bit grayscale 24 bit RGB color
Spatial Resolution	3000 to 5000 pixels across the long dimension
Spatial Dimensions	100% of original

Maps
File Format	TIFF (uncompressed)
Bit Depth	8 bit grayscale 24 bit RGB color
Spatial Resolution	3000 to 5000 pixels across the long dimension
Spatial Dimensions	100% of original

Graphic Materials
File Format	TIFF (uncompressed)
Bit Depth	8 bit grayscale 24 bit RGB color
Spatial Resolution	3000 to 5000 pixels across the long dimension
Spatial Dimensions	100% of original

It is recommended that images taken with a digital camera be captured at the highest possible quality. Our recommendation is to use at least a 2 mega pixel file with a minimum pixel array of 1,600 x 1,200 pixels.

As with the other image source types, it is always best to save the file as an uncompressed TIFF. The RAW format may also be used, but due to the file format’s proprietary and vendor specific nature it is best to convert it to a TIFF once it is moved to your computer.

At this time, the University Digital Conservancy is interested only in acquiring and preserving file formats of a high quality. Low resolution images for use primarily on web sites should not be included in the repository. We are also not in a position at this time to begin to accept vector-based images, such as those created through graphics programs or computer-aided design (CAD) software.

References

“Digital Photographic Images Guidelines”
Bentley Historical Library, University of Michigan
http://bentley.umich.edu/bhl/uarphome/imageguide.pdf

“Digital Imaging Best Practices: Version 1.0”
Western States Digital Standards Group
Collaborative Digitization Program
http://www.cdpheritage.org/digital/scanning/documents/WSDIBP_v1.pdf

Go to the UDC home page