The chemical sodium thiosulphate (formerly called hyposulphite) used as a photographic fixer.
- I use four teaspoons of hypo (sodium thiosulfate) in a liter of water and add a quarter-ounce of solution B.
- Salted paper is usually fixed in a 10% solution of hypo (100 grams of sodium thiosulfate in 1 liter of water) for 10 minutes.
- The print was toned for 2 minutes in selenium toner, followed by a 3 minute wash, 3 minutes in hypo clearing agent, and a 1 hour wash.
mid 19th century: abbreviation of hyposulphite.
noun (plural hypos)
early 20th century: abbreviation.
Entry from British & World English dictionary