Technical metadata

Long-term management and preservation of digital resources requires information about the technical characteristics of the digital content. Such technical metadata about text, image, audio and video data is best created when the digital content is originally created.

In our example case, we create PREMIS Object technical metadata for five different files. In METS they all follow the following notation:

<mets:md ID="[id]" USE="TECHNICAL"> 
  <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
    <mets:xmlData>
      <premis:object xsi:type="premis:file">
        [...]
      </premis:object>
    </mets:xmlData>
  </mets:mdWrap>
</mets:md>

In the <mets:md> element, the ID and USE attributes describe the identifier and use of the metadata section, respectively. For technical metadata, we recommend using the value TECHNICAL for the USE attribute. The <mets:mdWrap> and <mets:xmlData> elements indicate that the metadata is embedded in the section in XML format. The MDTYPE and MDTYPEVERSION attributes indicate that the type of the included metadata is PREMIS Object version 3.0.

In our example, the PREMIS Object metadata is created separately for each of the five included files. They are all listed below:

  • File 1 - Paper (DOCX): iPRES2023_METS_Tutorial.docx
    Technical metadata section in PREMIS
    <mets:md ID="tech-001" USE="TECHNICAL">
      <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
      <mets:xmlData>
        <premis:object xsi:type="premis:file">
        <premis:objectIdentifier>
          <premis:objectIdentifierType>local</premis:objectIdentifierType>
          <premis:objectIdentifierValue>file-001</premis:objectIdentifierValue>
        </premis:objectIdentifier>
        <premis:objectCharacteristics>
          <premis:compositionLevel>0</premis:compositionLevel>
          <premis:fixity>
          <premis:messageDigestAlgorithm authority="cryptographicHashFunctions"
            authorityURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions"
            valueURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/md5">MD5</premis:messageDigestAlgorithm>
          <premis:messageDigest>dbf121ba5952a3b48528e2d032b00ad3</premis:messageDigest>
          </premis:fixity>
          <premis:size>51554</premis:size>
          <premis:format>
          <premis:formatDesignation>
            <premis:formatName>Microsoft Word for Windows</premis:formatName>
            <premis:formatVersion>2007 onwards</premis:formatVersion>
          </premis:formatDesignation>
          <premis:formatRegistry>
            <premis:formatRegistryName>PRONOM</premis:formatRegistryName>
            <premis:formatRegistryKey>fmt/412</premis:formatRegistryKey>
            <premis:formatRegistryRole
              authority="http://id.loc.gov/vocabulary/preservation/formatRegistryRole"
              valueURI="http://id.loc.gov/vocabulary/preservation/formatRegistryRole/spe">specification</premis:formatRegistryRole>
          </premis:formatRegistry>
          </premis:format>
        </premis:objectCharacteristics>
        <premis:originalName>iPRES2023_METS_Tutorial.docx</premis:originalName>
        </premis:object>
      </mets:xmlData>
      </mets:mdWrap>
    </mets:md>
    
  • File 2 - Presentation (PPTX): 1702_1A_Bredenberg.pptx
    Technical metadata section in PREMIS
    <mets:md ID="tech-002" USE="TECHNICAL">
      <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
      <mets:xmlData>
        <premis:object xsi:type="premis:file">
        <premis:objectIdentifier>
          <premis:objectIdentifierType>local</premis:objectIdentifierType>
          <premis:objectIdentifierValue>file-002</premis:objectIdentifierValue>
        </premis:objectIdentifier>
        <premis:objectCharacteristics>
          <premis:compositionLevel>0</premis:compositionLevel>
          <premis:fixity>
          <premis:messageDigestAlgorithm authority="cryptographicHashFunctions"
            authorityURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions"
            valueURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/md5">MD5</premis:messageDigestAlgorithm>
          <premis:messageDigest>58806238a5c0d08afa2aa4cc59dc7238</premis:messageDigest>
          </premis:fixity>
          <premis:size>1233701</premis:size>
          <premis:format>
          <premis:formatDesignation>
            <premis:formatName>Microsoft Powerpoint for Windows</premis:formatName>
            <premis:formatVersion>2007 onwards</premis:formatVersion>
          </premis:formatDesignation>
          <premis:formatRegistry>
            <premis:formatRegistryName>PRONOM</premis:formatRegistryName>
            <premis:formatRegistryKey>fmt/215</premis:formatRegistryKey>
            <premis:formatRegistryRole
              authority="http://id.loc.gov/vocabulary/preservation/formatRegistryRole"
              valueURI="http://id.loc.gov/vocabulary/preservation/formatRegistryRole/spe">specification</premis:formatRegistryRole>
          </premis:formatRegistry>
          </premis:format>
        </premis:objectCharacteristics>
        <premis:originalName>1702_1A_Bredenberg.pptx</premis:originalName>
        </premis:object>
      </mets:xmlData>
      </mets:mdWrap>
    </mets:md>
    
  • File 3 - Handout (PDF): METS Exercise iPRES 2023.pdf
    Technical metadata section in PREMIS
    <mets:md ID="tech-003" USE="TECHNICAL">
      <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
      <mets:xmlData>
        <premis:object xsi:type="premis:file">
        <premis:objectIdentifier>
          <premis:objectIdentifierType>local</premis:objectIdentifierType>
          <premis:objectIdentifierValue>file-003</premis:objectIdentifierValue>
        </premis:objectIdentifier>
        <premis:objectCharacteristics>
          <premis:compositionLevel>0</premis:compositionLevel>
          <premis:fixity>
          <premis:messageDigestAlgorithm
            authority="cryptographicHashFunctions"
            authorityURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions"
            valueURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/md5">MD5</premis:messageDigestAlgorithm>
          <premis:messageDigest>ace57c041cef79977c87353e96475d58</premis:messageDigest>
          </premis:fixity>
          <premis:size>253648</premis:size>
          <premis:format>
          <premis:formatDesignation>
            <premis:formatName>Acrobat PDF 1.7 - Portable Document Format</premis:formatName>
            <premis:formatVersion>1.7</premis:formatVersion>
          </premis:formatDesignation>
          <premis:formatRegistry>
            <premis:formatRegistryName>PRONOM</premis:formatRegistryName>
            <premis:formatRegistryKey>fmt/276</premis:formatRegistryKey>
            <premis:formatRegistryRole
              authority="http://id.loc.gov/vocabulary/preservation/formatRegistryRole"
              valueURI="http://id.loc.gov/vocabulary/preservation/formatRegistryRole/spe">specification</premis:formatRegistryRole>
          </premis:formatRegistry>
          </premis:format>
        </premis:objectCharacteristics>
        <premis:originalName>METS Exercise iPRES 2023.pdf</premis:originalName>
        </premis:object>
      </mets:xmlData>
      </mets:mdWrap>
    </mets:md>
    
  • File 4 - Paper PDF: iPRES2023_submission_1702.pdf
    Technical metadata section in PREMIS
    <mets:md ID="tech-004" USE="TECHNICAL">
      <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
      <mets:xmlData>
        <premis:object xsi:type="premis:file">
        <premis:objectIdentifier>
          <premis:objectIdentifierType>local</premis:objectIdentifierType>
          <premis:objectIdentifierValue>file-004</premis:objectIdentifierValue>
        </premis:objectIdentifier>
        <premis:objectCharacteristics>
          <premis:compositionLevel>0</premis:compositionLevel>
          <premis:fixity>
          <premis:messageDigestAlgorithm authority="cryptographicHashFunctions"
            authorityURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions"
            valueURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/md5">MD5</premis:messageDigestAlgorithm>
          <premis:messageDigest>0b17b66e1c8ec8bb3074e9d5d3dd5623</premis:messageDigest>
          </premis:fixity>
          <premis:size>103555</premis:size>
          <premis:format>
          <premis:formatDesignation>
            <premis:formatName>Acrobat PDF 1.4 - Portable Document Format</premis:formatName>
            <premis:formatVersion>1.4</premis:formatVersion>
          </premis:formatDesignation>
          <premis:formatRegistry>
            <premis:formatRegistryName>PRONOM</premis:formatRegistryName>
            <premis:formatRegistryKey>fmt/18</premis:formatRegistryKey>
            <premis:formatRegistryRole
              authority="http://id.loc.gov/vocabulary/preservation/formatRegistryRole"
              valueURI="http://id.loc.gov/vocabulary/preservation/formatRegistryRole/spe">specification</premis:formatRegistryRole>
          </premis:formatRegistry>
          </premis:format>
        </premis:objectCharacteristics>
        <premis:originalName>iPRES2023_submission_1702.pdf</premis:originalName>
        </premis:object>
      </mets:xmlData>
      </mets:mdWrap>
    </mets:md>  
    
  • File 5 - Presentation PDF: METS Tutorial iPRES 2023.pdf
    Technical metadata section in PREMIS
    <mets:md ID="tech-005" USE="TECHNICAL"> 
      <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
        <mets:xmlData>
          <premis:object xsi:type="premis:file">
            <premis:objectIdentifier>
              <premis:objectIdentifierType>local</premis:objectIdentifierType>
              <premis:objectIdentifierValue>file-005</premis:objectIdentifierValue>
            </premis:objectIdentifier>
            <premis:objectCharacteristics>
              <premis:compositionLevel>0</premis:compositionLevel>
              <premis:fixity>
                <premis:messageDigestAlgorithm authority="cryptographicHashFunctions"
                  authorityURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions"
                  valueURI="http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/md5">MD5</premis:messageDigestAlgorithm>
                <premis:messageDigest>0c171c6ecab670343e02cd0f26e85385</premis:messageDigest>
              </premis:fixity>
              <premis:size>972257</premis:size>
              <premis:format>
                <premis:formatDesignation>
                  <premis:formatName>Acrobat PDF 1.7 - Portable Document Format</premis:formatName>
                  <premis:formatVersion>1.7</premis:formatVersion>
                </premis:formatDesignation>
                <premis:formatRegistry>
                  <premis:formatRegistryName>PRONOM</premis:formatRegistryName>
                  <premis:formatRegistryKey>fmt/276</premis:formatRegistryKey>
                  <premis:formatRegistryRole
                    authority="http://id.loc.gov/vocabulary/preservation/formatRegistryRole"
                    valueURI="http://id.loc.gov/vocabulary/preservation/formatRegistryRole/spe">specification</premis:formatRegistryRole>
                </premis:formatRegistry>
              </premis:format>
            </premis:objectCharacteristics>
            <premis:originalName>METS Tutorial iPRES 2023.pdf</premis:originalName>
          </premis:object>            
        </mets:xmlData>
      </mets:mdWrap>
    </mets:md>
    

As the 6th technical metadata section, we add a PREMIS Intellectual Entity of the full tutorial. The METS elements are similar to the corresponding elements in the PREMIS Object metadata of the files.

<mets:md ID="tech-006" USE="TECHNICAL">
  <mets:mdWrap MDTYPE="PREMIS:OBJECT" MDTYPEVERSION="3.0">
  <mets:xmlData>
    <premis:object xsi:type="premis:intellectualEntity">
    <premis:objectIdentifier>
      <premis:objectIdentifierType authority="identifiers"
        authorityURI="http://id.loc.gov/vocabulary/identifiers"
        valueURI="http://id.loc.gov/vocabulary/identifiers/hdl" >hdl</premis:objectIdentifierType>
      <premis:objectIdentifierValue>https://hdl.handle.net/2142/121056</premis:objectIdentifierValue>
    </premis:objectIdentifier> 
    </premis:object>
  </mets:xmlData>
  </mets:mdWrap>
</mets:md>