Biblatex: No "pp." in front of pages if pages field contains colon

Question

I have noticed that the output of biblatex for a entry of type @inproceedings is missing the "pp." in front of the pages if the pages-field of the entry is of the shape x:1--x:15. I strongly assume this is because the colon is detected as punctuation, but I could be wrong about this. How can I make sure that I get the "pp."?

Example:

\documentclass{scrbook}
\begin{filecontents}{bibfile.bib}
@inproceedings{Test1,
    author    = {Author One},
    title     = {Papertitle},
    booktitle = {Proceedingstitle},
    year      = {2000},
    volume    = {1},
    series    = {Series},
    pages     = {1--5},
}
@inproceedings{Test2,
    author    = {Author Two},
    title     = {Another Papertitle},
    booktitle = {Another Proceedingstitle},
    year      = {2020},
    volume    = {2},
    series    = {Series},
    pages     = {3:1--3:15},
}
\end{filecontents}
\usepackage[style=alphabetic]{biblatex}
\addbibresource{bibfile.bib}
\begin{document}
\nocite{*}
\printbibliography
\end{document}

The output for Test1 is expected and contains "pp.":

Author One. “Papertitle”. In: Proceedingstitle. Vol. 1. Series. 2000, pp. 1–5.

The output for Test2 is missing the "pp.":

Author Two. “Another Papertitle”. In: Another Proceedingstitle. Vol. 2. Series. 2020, 3:1–3:15.

Answer 1

biblatex usually checks if something is a valid page/page range before it places "p."/"pp.". The colon is not among the default set of "numeric" characters and so will tell biblatex that we are not dealing with a page range.

We can tell biblatex to accept colons with

\documentclass{scrbook}
\usepackage[style=alphabetic]{biblatex}
\DeclareNumChars*{:}
\begin{filecontents}{\jobname.bib}
@inproceedings{Test1,
    author    = {Author One},
    title     = {Papertitle},
    booktitle = {Proceedingstitle},
    year      = {2000},
    volume    = {1},
    series    = {Series},
    pages     = {1--5},
}
@inproceedings{Test2,
    author    = {Author Two},
    title     = {Another Papertitle},
    booktitle = {Another Proceedingstitle},
    year      = {2020},
    volume    = {2},
    series    = {Series},
    pages     = {3:1--3:15},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
\nocite{*}
\printbibliography
\end{document}

Often these two-part page numbers are supposed to tell us about an "article/paper number" and the number of pages of such a paper, in that case you can split the info into the eid field for the article/paper number and pages for the pure page range (which is often pointless in these cases unless you absolutely want to give an indication of the length of the paper).

\documentclass{scrbook}
\usepackage[style=alphabetic]{biblatex}
\begin{filecontents}{\jobname.bib}
@inproceedings{Test1,
    author    = {Author One},
    title     = {Papertitle},
    booktitle = {Proceedingstitle},
    year      = {2000},
    volume    = {1},
    series    = {Series},
    pages     = {1--5},
}
@inproceedings{Test2,
    author    = {Author Two},
    title     = {Another Papertitle},
    booktitle = {Another Proceedingstitle},
    year      = {2020},
    volume    = {2},
    series    = {Series},
    eid       = {3},
    pages     = {1-15},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
\nocite{*}
\printbibliography
\end{document}