Colorchecker Passport in Solar UV

[Andrea B.]

Finally, I reasoned that to slightly exceed the NIR blocking of conventional UV-bandpass filters is sufficient.

 

This seems reasonable to me. You would want OD3 or OD4, I think.

 

I use sunlight or UV flash or a combination depending on the subject.

• Does IR leakage affect more the longer UV or the shorter UV - longer/shorter being relative to the 300-400nm band?
  

• Could a filter like the CopperU be stacked with an IR blocker in those cases where IR leakage might be affecting the outcome?
  

[rfcurry]

Col,

 

The 365nm range may be good for some applications, but in shooting biologicals, it would seem best to pattern the UV input to the solar intensity. Thus, 400nm would be most intense, dropping rather quickly to the 320nm range. Also, some botanicals will have markings associated with their pollinating insect or bird, and the pollinator's optimum UV vision may be at 340nm, so a 365nm light is not going to reveal the markings. A series of UV bandpass filters, with very narrow bands, might seem a good approach, however, the narrow bandpass dichroic filters tend to be expensive and usually only pass 15% or so at their peak. Perhaps the optimum approach would be to use a wide bandpass UV fillter and narrow band UV emitters.