F-24 Non-Hardening Fixer

F-24 Non-Hardening Fixer is the non-hardening variant of Kodak's F-5 hardening fixer family. Same sodium-thiosulfate fixing chemistry as F-5, but without the potassium alum hardener — used when print preservation workflow doesn't require hardened gelatin and faster wash times are preferred.

Key features

• Sodium thiosulfate fixer (like F-5, not the faster ammonium thiosulfate of Rapid Fixer)
• Non-hardening: no potassium alum; gelatin emulsion remains soft
• Faster wash than F-5: ~15-20 min for fiber prints vs F-5's 30+ min
• Same fixing time as F-5: 5-10 min for film, 5-10 min total for fiber paper
• Buffered with boric acid for stability

Workflow

Material	Time
35mm/120 film	5-10 minutes (use 2× clearing time)
Fiber paper	2 baths × 5 min each (archival)
RC paper	1-2 minutes total

Capacity: ~25 8x10 prints per liter or ~5-6 rolls of film per liter.

Practical notes

• Mix from individual chemicals (no commercial pre-mix)
• Choose F-24 over F-5 when modern darkroom handling makes hardening unnecessary
• Choose F-24 over Rapid Fixer when sodium thiosulfate is preferred over ammonium thiosulfate (rare; some chlorobromide papers may benefit)
• Always use stop bath before F-24
• Use HCA or Perma Wash for fiber prints to optimize wash time
• PPE: nitrile gloves and eye protection

Related recipes

• [[recipe-kodak-fixer-f-5|Kodak Fixer (F-5)]] — the hardening variant
• [[recipe-rapid-fixer|Rapid Fixer]] — faster ammonium thiosulfate alternative
• [[recipe-tf-4-alkaline-fixer|TF-4 Alkaline Fixer]] — alkaline non-hardening alternative with even faster wash
• [[recipe-citric-acid-stop-bath|Citric Acid Stop Bath]] — required pre-fix step
• [[recipe-hypo-clearing-agent|Hypo Clearing Agent]] — wash-aid step