After further testing guided by Hans’ suggestion, I now have

\setupexternalfigures[location=default]
\setuplayer[preset=rightbottom, method=overlay]{}
\setuppagenumbering[color=darkmagenta]
\starttext
\getfiguredimensions[HannahBW.pdf]

\dorecurse{\noffigurepages}{
\startTEXpage[pagestate=start]
\layeredtext[]
[boffset=3pc, roffset=3pc]
{\darkmagenta\subpagenumber}
{\externalfigure[HannahBW.pdf][page=#1]}
\stopTEXpage
}
\stoptext

which works, though it would arguably be better if there is a way to
prevent the subpage number on the first page of every included file.

Alan

On Fri, Sep 25, 2020 at 6:12 AM Hans Hagen <j.hagen@xs4all.nl> wrote:

> On 9/25/2020 5:53 AM, Aditya Mahajan wrote:
> > On Fri, 25 Sep 2020, Wolfgang Schuster wrote:
> >
> >> Aditya Mahajan schrieb am 24.09.2020 um 23:48:
> >>> On Thu, 24 Sep 2020, Alan Bowen wrote:
> >>>> Any suggestions or pointers will be most welcome.
> >>>
> >>> See if this gives you any ideas ....
> >>>
> >>> https://adityam.github.io/context-blog/post/include-multi-page-pdf/
> >>
> >> When both document have the same size you can replace TeXpage with a
> "page"
> >> layout.
> >>
> >> \startlayout[page]
> >> \dorecurse{\noffigurepages}{\externalfigure[...][page=\recurselevel]}
> >> \stoplayout
> >
> > Thanks for the comment (also I didn't know about \startlayout ..
> \stoplayout). Unfortunately, in my use case, the paper sizes may not be the
> same.. I am typically attaching published journal articles and some are
> published on letter paper and some on A4.
>
> \setupexternalfigures[location=default]
>
> \starttext
>
> \dorecurse {5} {Before #1\page}
>
> \getfiguredimensions[oeps.pdf]
>
> \startsetups SomeNumber
>      \vbox to \overlayheight \bgroup
>          \vss
>          \hbox to \overlaywidth \bgroup
>              \hss
>                  \bfd \red You can figure it out: \pagenumber
>              \hss
>          \egroup
>          \vss
>      \egroup
> \stopsetups
>
> \defineoverlay[SomeNumber][\setups{SomeNumber}]
>
> \dorecurse {\noffigurepages} {
>      \startTEXpage[pagestate=start]
>          \externalfigure[oeps.pdf][page=#1,background=SomeNumber]%
>      \stopTEXpage
> }
>
> \dorecurse {5} {After #1\page}
>
> \stoptext
>
> -----------------------------------------------------------------
>                                            Hans Hagen | PRAGMA ADE
>                Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
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