DictionaryhypoPhotographic fixing chemical
noun

hypo

Sodium thiosulfate used to fix photographic images.

The photographer prepared a hypo fixing bath.

Etymology

Hypo shortens hyposulphite, an older chemical name used for the fixing agent. Photography retained the shortened name after sodium thiosulfate became the preferred chemical designation.

More examples

  • The old darkroom manual specified hypo for fixing the print.
  • A container of hypo stood beside the developing tray.
  • The archival note discussed removing residual hypo from photographs.

Forms

hypo

Similar words

fixer
Fixer is the photographic solution that makes an image permanent; hypo names a chemical used in such solutions.