PREMIS and the National Digital Newspaper Program

1
PREMIS and the National Digital Newspaper Program

• Justin Littman
• Office of Strategic Initiatives, LC
• jlit_at_loc.gov

2
Overview

• Repository of digitized, historical newspapers
• Implemented PREMIS in 2005
• To date, applied to 1.2 million digital objects

3
What we do

• PREMIS metadata for each file
• TIFF
• PDF
• JP2
• ALTO
• METS (subset of metadata)
• PREMIS metadata is included as lttechMDgt in METS

4
What we do - example

• lt!--PREMIS technical metadata for digital master
  for page 1--gt
• lttechMD ID"masterPremis1"gt
• ltmdWrap MDTYPE"OTHER" OTHERMDTYPE"PREMIS"
  LABEL"PREMIS object metadata"gt
• ltxmlDatagt
• ltpremisobjectgt
• ltpremisobjectCharacteristicsgt
• ltpremisfixitygt
• ltpremismessageDigestAlgorithmgtSHA-1lt/
  premismessageDigestAlgorithmgt
• ltpremismessageDigestgtlt!--SHA-1
  checksum (Required)--gt lt/premismessageDigestgt
• ltpremismessageDigestOriginatorgtLibrar
  y of Congresslt/premismessageDigestOriginatorgt
• lt/premisfixitygt
• ltpremissizegt1lt/premissizegtlt!--Size of
  the file in bytes.(Required)--gt
• ltpremisformatgt
• ltpremisformatDesignationgt
• ltpremisformatNamegtimage/tifflt/premi
  sformatNamegt
• lt/premisformatDesignationgt
• lt/premisformatgt

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What we do example, continued

• ltpremissignificantPropertiesgt
• ltndnpexemptionSetgt
• ltndnpcodegtTEST1lt/ndnpcodegt
• ltndnpcodegtTEST2lt/ndnpcodegt
• lt/ndnpexemptionSetgt
• lt/premissignificantPropertiesgt
• lt/premisobjectCharacteristicsgt
• ltpremiscreatingApplicationgt
• ltpremiscreatingApplicationNamegtlt!--crea
  tingApplicationName (optional)--gtlt/premiscreating
  ApplicationNamegt
• ltpremiscreatingApplicationVersiongtlt!--c
  reatingApplicationVersion (optional)--gtlt/premiscr
  eatingApplicationVersiongt
• ltpremisdateCreatedByApplicationgt2004-11
  -22T000000lt/premisdateCreatedByApplicationgtlt!--
  dateCreatedByApplication (required for master)--gt
• lt/premiscreatingApplicationgt
• lt/premisobjectgt
• lt/xmlDatagt
• lt/mdWrapgt
• lt/techMDgt

6
What we do - related

• MIX metadata for each image file
• Enveloped XML digital signature for METS file
• Modified PREMIS schema to omit some mandatory
  elements
• ltobjectIdentifiergt
• ltobjectCategorygt

7
How we do it

• PREMIS is generated and inserted into METS by
  NDNP Validation Library
• PREMIS is created by an XSLT transformation of
  representation information produced by JHOVE

8
Lessons learned

• Would prefer PREMIS schema to be more modular
• Shift in (personal) philosophy For
  technical/preservation metadata, less is more
• Collect metadata for immediate needs
• Cant guess what will be needed in the future
• If metadata can be derived, then derive when
  necessary

9
Lessons learned, continued

• PREMIS as reference model rather than
  implementation model
• Fixities stored in METS/PREMIS require custom
  tools to verify
• Simpler approaches / common utilities more
  interoperable