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Small Particle Reagent (Wet Print)

View a short video demonstration.

Most people you talk to will tell you that if an item is wet you can not process it for latent fingerprints or if it was wet when it was grabbed you won't get any prints off it. Let's say you found a cold beer can at a crime scene with condensation all over it because it came out of the refrigerator into the warmer air. You have to let it dry out first to process it, right? Wrong! You can take the item or vehicle and process it while it is wet by using small particle reagent (wet print).

The next thing they will tell you is once you develop a latent print with small particle reagent (wet print) you will have to let it dry before you can lift it from the surface. Wrong again! You can lift the latent fingerprint while it is still wet. If you look at the small particle reagent (wet print) print after you have developed and rinsed it with water, you will notice that in the area of the latent print the water has beaded away from the latent fingerprint. Place the lifting tape down directly onto the latent print pushing in the center then working outwards to remove the excess water. Lift the print and place on a contrasting backing card.

small particle reagent (wet print) is like liquid fingerprint powder. When sprayed on the surface of non-porous wet evidence, the micro fine particles attach themselves to the latent print residues as the solution runs off the surface. The residue is sprayed with water to remove excess solution and the developed latent fingerprints can be lifted with lifting tape.

Potential Uses:

Processing non-porous items covered with water or snow.

Developing latent prints on non-porous items that have been lightly washed.

Processing items in situations where mud, dirt, or heavy dust has covered prints making them impossible to develop by conventional means.

For optimum results:

Always use fine, soft mist when spraying.

small particle reagent (wet print) dries silver on dark objects and dark on light-colored objects and is available in white also.

To use small particle reagent (wet print) on wet objects:

1) Be sure spray nozzle is in "off" position before shaking and after using to prevent leaking.

2) Shake small particle reagent (wet print) container to disperse solids. This needs to be done frequently during the spraying process because the particle reagent is heavier than the water and will settle to the bottom of the spray container.

3) Adjust spray nozzle for fine, soft spray and test the spray before applying.

4) Spray small particle reagent (wet print) onto the wet surface allowing the agent to roll down and spread over the suspected fingerprint area. It is best to start at the top and work to the bottom of the item.

5) Spray area with clear water to wash off the excess small particle reagent (wet print) to view the developed prints.

6) If needed, repeat steps 4 and 5 until print is completely developed.

7) If details in the print appear to be clogged with residual small particle reagent (wet print), spray a fine mist of clear water over the developed latent fingerprint.

8) Once prints are fully developed, photograph and either let dry or lift wet by placing the lifting tape onto the print and working from the center out. Press the tape down to remove the excess water. Place tape on backing card and again press the tape down to remove any excess water.

9) Dried print may then be re-photographed and lifted by conventional means.

To use small particle reagent (wet print) on dry objects:

1) Be sure spray nozzle is in "off" position before shaking and after using to prevent leaking.

2) Shake small particle reagent (wet print) container to disperse solids. This needs to be done frequently during the spraying process because the particle reagent is heavier than the water and will settle to the bottom of the spray container.

3) Adjust spray nozzle for fine, soft spray and test the spray before applying. If item is particularly dirty, spray with a fine mist of water until all dirt washes away. Do not wipe suspected fingerprint area.

4) Proceed with processing following steps 4 through 9 that are listed above for wet objects.

small particle reagent (wet print) can be purchased in both pre-mixed solution and powder that you mix.

The small particle reagent (wet print) can be purchased through the Lynn Peavey Company.

 




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