1. Lightly spray Zinc Chloride onto the item until coated. 

2. Allow item to air dry completely. If using a humidity chamber, settings should not exceed 80°C and 80% relative humidity.

3. Ridges will change from purple (if previously developed with ninhydrin or ninhydrin analog) to an orange/red color when the reaction is complete. If the color change is not noted, successive light applications may be applied.

4. View ridge detail using a laser or a forensic light source. For ninhydrin or 5-M.T.N. treated items, view in the 450 – 530nm range with orange or red googles. For 1,2 indanedione treated items, view in the 515 – 570nm range with orange or red goggles. 

5. Capture ridge detail using 1:1 photography. For ninhydrin or 5-M.T.N. treated items, use an orange colored or 550 (BP 35) bandpass filter. For 1,2 indanedione treated items, use an orange or red 600 (BP 35) barrier filter.