What might analysts be able to use tunable lights for?

This is for a forensics class.

Explanation:

crime scene investigators and forensic examiners are now using "alternate light sources" to identify residues and prints which cannot be seen under normal light conditionscould there be a role for them to this end?

is this a psat question, if so do not cheat try your best.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.