This function returns the UVA1:UV photon ratio of a light source spectrum.
Arguments
- spct
an object of class "source.spct".
- std
select which definition of UVA1 should be used, defaults to "CIE". For UV "ISO" is always used.
- use.cached.mult
logical indicating whether multiplier values should be cached between calls.
- use.hinges
logical indicating whether to use hinges to reduce interpolation errors.