What happens to the image produced by iodine vapor if it is not fixed?

When using iodine vapor to develop latent fingerprints, the process creates transient images that are not stable. If the developed image is not fixed, it will gradually fade over time. This fading occurs because iodine-substantiated prints are dependent on the presence of iodine molecules that will slowly dissipate, thereby causing the visibility of the fingerprint to diminish.

In contrast, if the fingerprint was fixed using a method such as a chemical fixative, the image would be preserved and stabilized, allowing for long-term viewing and documentation. Consequently, without fixing, the latent print will not only fade but may eventually become invisible, leading to loss of valuable evidence. This is key in forensic practices as proper handling and preservation of evidence are critical for investigation integrity.