Presentation on theme: "足迹 FOOTPRINT. 2D- once the print is photographed it can be lifted with a gel lifter, shoe impression lifters or fingerprint tape. When using fingerprint."— Presentation transcript:
2D- once the print is photographed it can be lifted with a gel lifter, shoe impression lifters or fingerprint tape. When using fingerprint tape the impression will have to be lifted in the same manner as a multi finger lift.
Enhancing 2-D prints The 2D print can sometimes be “ developed ” in much the same way as a fingerprint by using black powder. The print can then be lifted and placed on acetate or white paper.
Electrostatic Dust Print Lifter about 20 years ago a recovery method was developed for collecting dust prints. This method uses an electrostatic charged piece of Mylar film to lift the prints.
The electrostatic dust lifter will work on virtually any surface. The print quality will vary because it is dependant upon the surface where the print is located.
If you have a stun gun you already have the major component of a dust print lifter. All you need is a piece of Mylar film to lift dust prints.
Methods of Recording Shoe Sole Impressions. a.Photography b.Documentation/sketching c.Lifting d.Casting
Sketching draw a diagram or sketch of the impression noting anything unique about.
Equipment needed: 1 gallon zip-loc bag or a plastic bucket 2 to 3 pounds of dental stone or plaster of Paris 6 to 9 ounces of water. Mix to a “ pancake ” dough consistency. Casting
Before pouring the mixture the impression needs to be prepared: If the impression is in a “sugar” sand or powdery medium the soil or medium will have to be “fixed”. Use a pump type bottle of hair spray and lightly coat the impression to fix it. Also remove any excess debris (leaves,twigs etc.).
“Fixing the Impression”
Beginning on one side of the impression pour the casting material and let it flow across the impression.
After the casting begins to dry “ scratch ” in all pertinent information. After about 30 minutes place a knife about 1 inch to one side and under the casting. Gently lift the casting free from the soil. Once the casting is removed it should be placed in a box or bag. Do not put it in plastic. It will continue to “ cure ” for several days. Excess dirt can be removed after 24 hours.