Nicholas Lindan
Advertiser
Well, almost.
Dichroic filters will pass/block multiples of the pass-band frequency. They are often combined with a regular old dye filter to absorb any unwanted harmonics.
For photographic applications this is only of academic interest.
When used for photometery the addition of an absorbance filter is often required: A filter used to analyze a chemical absorbance at 700nm (deep red) would also pass 350nm (deep purple) and so a red dye filter is sandwiched with the dichroic.
