You will need
- - source oblique lighting;
- - special spray.
To reveal fingerprints on smooth surfaces, use cocoadile lighting. Aim at the object or surface a beam of light at a certain angle. The fingerprints, if any, on the surface, are clearly visible. A prerequisite for this investigation is not to leave the subject of his prints, which can lubricate the existing picture. This method is convenient to detect the traces on the furniture, polished or varnished surfaces of articles, for example, on appliances.
If you want to detect the finger traces on a ceramic or glass container, then use the same method, but it is possible to do without artificial light source. Gently take the object over the edge and bring to the lighted window. In clear weather, falling at an angle to the surface of the glass sun's rays will replace the light bulb.
For the detection and recording of fingerprints on wet surfaces, use special tools, for example, an aerosol “SPR”. It is a special solution that can identify fingerprints on wet nonporous surface. This method is the powder method, which found application in forensic science.
Shake the can of aerosol. Then spray the product evenly on the vertical surface where you intend to detect fingerprints. Use the cylinder with a distance of 20-30 cm after a few seconds the place that the processed composition will manifest the desired prints.
Wait until the composition is fully dry, after which the prints can be separated and preserved for later study. If possible, pre-produce the photograph shown traces before their removal from the surface.
Use the spray for prints with vertical surfaces as on horizontal subjects the liquid does not spread and is in one place, making it difficult to detect finger prints.