Direct Transfer Method of Latent Fingerprint Development With Procedure

The direct Transfer Method is a method used for transferring the latent marks and fingerprints from the skin surface, before development onto a clean substrate such as on glass, sheet, etc. The direct transfer technique started with iodine and electrographic techniques in which the transfer mediums were rolled against the surface of human skin. 

When Direct Transfer Method is Used? (Need)

• Helps to visualize the latent marks clearly which is useful for the examination.
• Another advantage of this method is that this removes the skin background that typically causes problems when development is attempted.
• By using the direct transfer method, ridge details of the latent fingerprint on the skin become more prominent which helps in identification.

Types of surfaces used in the method:

Surfaces	Description
Glass	One of the best surfaces to detect latent marks.
Plastic film	Provides good results
Glossy paper like kromekote card	Good results are obtained.
PET/ photographic paper	Useful over a week old latent marks.

How to Develop Fingerprints Using Direct Transfer Method?

Material Required

Using Surfaces	Material Required
Glass	Clean glass sheet, fingerprint powder, illuminator, fingerprint brush
Plastic Film	Semi-rigid PET sheet, source of oblique lighting, fingerprint brush
Glossy Paper	Paint roller, fingerprint powder, fingerprint brush

Procedure

First, before selecting any transfer medium, a target area with the fingerprint of the skin should be established.

Method A: For the GRIT (Glass Recovery Investigative) Method

• Sampson proposed this technique as glass is one of the best surfaces to detect latent marks.
• The clean glass slide is placed over the skin.
• After the transfer procedure, fingerprint powders or fuming methods, or episodic coaxial illumination is applied to reveal any ridge details. 

Method B: Alternative of GRIT technique (using plastic film)

• The sheet should be relatively thick but pliable enough to easily conform to most body contours.
• The plastic film should be placed carefully on the selected area and must be removed slightly.
• The transferred marks can be then fumed with CA or dusted with conventional powder.

Method C: Using PET Sheet 

• The sheet is electrostatically charged by vigorous rubbing and then pressed onto the surface of interest.
• The charged sheet will attract any dust present in the latent mark.
• The transferred marks are then visualized by oblique lighting.

Method D: Using Glossy paper (e.g kromekote card)

• Press the paper or card to the surface of the skin with moderate pressure. A paint roller can also be used. 
• The paint roller should be rolled in a swift motion over the back of the paper/ card after it is applied to the skin.
• The paper should be removed immediately by carefully starting at one corner.

Lifting Prints and Photography 

For lifting latent marks a casting method is used. In casting methods, Silicone casting is generally used. Care should be taken before directly applying the casting method. Other detection methods can then be applied to gain additional ridge details. 

For photography,  oblique lighting is used. The light source is placed over the area where the latent mark is present. Then using a good quality camera the photography must be taken.

Read More: Photographing Shoe & Tire Marks on Snow With Highlighting Materials

References:

• Direct Transfer method using Copy Paper [Pdf]
• Obtaining Latent Prints from the Skin of a Living Person [GMU.edu]
• Fundamentals of Fingerprint Analysis, Second Edition By Hillary Moses Daluz [book]