If you include
  xmlns="http://www.loc.gov/mods/v3"
in the <mods> root element you don't need the prefixes.

For example, try this:
at
http://lcweb2.loc.gov/diglib/ihas/loc.afc.afc9999005.1153/mets.xml

line 6 is
<mods:mods ID="mods1">

Replace it with:
         <mods ID="mods1" xmlns="http://www.loc.gov/mods/v3">
And remove the "mods:" prefixes, and it validates fine.

Ray


> -----Original Message-----
> From: Metadata Object Description Schema List
> [mailto:[log in to unmask]] On Behalf Of McAulay, Elizabeth
> Sent: Monday, December 15, 2014 9:30 AM
> To: [log in to unmask]
> Subject: Re: [MODS] MODS mdWrap question
>
> Hi Michele,
>
> Yes, I believe the prefixes are required to distinguish which tags are MODS
> and which are METS. This helps for keeping the files valid and conformant to
> the XML standard.
>
> Best,
> Lisa
>
> > On Dec 15, 2014, at 6:23 AM, "Michele R Combs" <[log in to unmask]>
> wrote:
> >
> > I have a METS file. In it I have mdWrap sections, e.g. Dublin Core and
> MODS:
> >
> > <mets:mdWrap MDTYPE="MODS">
> > <mets:xmlData>
> > <mods:identifier displayLabel="ID Number"
> type="local">8094</mods:identifier>
> > <mods:typeOfResource>still image</mods:typeOfResource>
> > <mods:titleInfo>
> > <mods:title>Addendum for U.C. Chapel Hill</mods:title>
> > </mods:titleInfo>
> > </mets:xmlData>
> > </mets:mdWrap>
> >
> > Since I've declared MDTYPE="MODS" for the mdWrap, do I still need the
> mods: namespace identifiers in the subelements, or are they assumed and
> therefore optional? Does the answer vary depending on what's processing
> the mets document?
> >
> > Thanks
> >
> > Michele
> > +++++++++++++++
> > Michele Combs
> > Lead Archivist
> > Special Collections Research Center
> > Syracuse University Libraries
> > 315-443-2081
> > [log in to unmask]
> > scrc.syr.edu