Superflux: "Get a large mirror to put in the drip zone and reflect up onto the area of interest?"
Ding Ding Ding, give the man a cigar.
I've used that method, and it works, but there are some things to keep in mind if you do.
Lets review some standard formula:
F=C/ƛ
F frequency
C speed of light
ƛ wavelength
Snells law written for optic refraction
N2/N1 = ƛ1/ƛ2
N1 index of refraction of air = 1.0
N2 index of refraction of glass = 1.6
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/indrf.htmlhttp://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html#c2The index of refraction for glass is the standard for 'crown glass'. Most modern mirrors use that, but remember there are 'flint glasses' and 'barium crown glasses'.
Why does that matter? Because there are multiple frequencies of light involved here. Specifically white light with a full visible spectrum of ~380-700nm, fluorescent bulb central frequency 365nm, and the fluoresced light from the inspection medium at around 525-575nm. Note: The longer wavelength is due to stokes shift caused by energy lost in the process of creating that fluorescence to begin with. More simply put, the shift in spectrum is due to that lost of energy.
That's a general overview of the background.
That is also why you cannot use what you see in the mirror to make a call, but you can use direct light of sight from the examiner to make that call. Simply put a meter on the inspection surface to make sure the mirror is delivering sufficient energy from your lamp, then use direct visual of the part to interpret the indications.
I've made that as simple as I can, but if you want specifics of why you can't use the mirror directly, shoot me a pm.