What is one method for preserving powdered fingerprints?

Preserving powdered fingerprints is essential for ensuring that the evidence can be effectively analyzed and used in investigations. Lifting or photographing the fingerprints is an effective method for this purpose. Lifting involves using adhesive tape or similar materials to capture the fingerprint directly from the surface it was found on. This method allows for the preservation of the print in its original form, which can then be documented and analyzed in a lab setting.

Photographing is another key technique; a high-resolution image captures the details of the fingerprint without altering its state. This also provides a permanent record that can be referenced in the future. Both lifting and photography ensure that the fingerprints can be studied and compared without risking damage to the original print, making it an ideal method for evidence preservation.

The other methods listed have limitations for preserving fingerprint evidence, such as potential damage to the print or contamination, which can hinder forensic analysis. Storing in an airtight container does not account for the specific needs of the powdered print itself, and soaking in alcohol or freezing can compromise the print's integrity. Thus, lifting or photographing is the most reliable and effective approach to preserving powdered fingerprints.