Why DNGs?

[rondlg]

DNGs are the recommended archive file format for Field Museum images contained with in the Museums' DAMS and EMu. There may be cases where other formats are required to be archived. Feel free to contact the helpdesk@fieldmusem.org if you would like help understanding DNGs.

A brief intro to "What is DNG?"

• DNG Standards Presentation July 2014. (Answers the question why we recommend DNGs)

• How DNGs behave in EMu (Working google spreadsheet including upload time information and references)

• Evaluating File Formats for Long Term Preservation Ref: Rog and Wijk2008

Software for converting TIFFs to DNGs (jan 2015)

• Lightroom
• "toDNG" is a ~$20 Mac program that might work.
• DxO Optics Pro is ~$100. It's similar to LR, but professional non-Adobe software. Caveat, though: we haven't had a chance to test it in EMu.
• Adobe is offering LR + PS (CC versions) for $10/mo

Four good criteria for evaluating archival formats:

• Storage Size (DNG = TIFF-LZW)
• Image Quality (DNG = TIFF-LZW; lossless)
• Format Sustainability (DNG > TIFF-LZW?)
• Format Functionality (DNG = TIFF-LZW)

"Sustainability" in terms of "what are the risks of archiving in a given format, considering openness, adoption, complexity, technical protection, documentation, robustness, and dependencies?"
"Functionality" considers technical spec's (what metadata can the format retain? does it function well as a high-res master? etc.)

This method comes from a 2008 paper on evaluating formats for long-term preservation...rabbit hole, but good info in it...