Diazafluoren-9-One (DFO)

• Develops 2.5x more prints than Ninhydrin
• Flammable - used in film hood, full-face mask, gloves
• Reacts with Amino Acids in fingerprint
• takes 24 hours to process without oven/hair dryer to accelerate development
• cannot be used on previously wet items (washes off amino acids)
• Shelf life - 6 months
• More sensitive to amino acids than Ninhydrin

When to use DFO over Ninhydrin?

Since Ninhydrin dries purple, use DFO on dark, purple or busy backgrounds

PROCEDURE:

1. Submerge or spray item 5 seconds
2. Dry item in fume hood
3. Repeat process steps 1 & 2
4. Dry or Accelerate with oven or hair dryer [@ 50-100°C 10-20 minutes]
5. MUST use Alternate Light Source (ALS) [495nm-550nm]
6. Red Filter (610nm-700nm) Bulb Setting 1½ - 2