Tracers are the experience of visual trails of varying lengths and opacity being left behind moving objects in a manner that is similar to those found in long exposure photography.  They will usually manifest as exactly the same colour of the moving object producing it or can sometimes be a randomly selected colour of their own.
A relatively consistent way to reproduce this visual effect is to simply move one's hand in front of their face or throw an object under the influence of a moderate dose of psychedelics.
This effect is capable of manifesting itself across the 4 different levels of intensity described below:
Tracers are often accompanied by other coinciding effects, such as drifting and after images. They are most commonly induced under the influence of mild dosages of psychedelic   compounds, such as LSD     , psilocybin, and mescaline. However, they can also occur less commonly under the influence of MDMA and certain dissociatives, such as 3-MeO-PCP or DXM.
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