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Fluorescence-Filter for underwater strobes (polyester foils or Dichroic-Glasfilter)

Underwater-Fluorescence depends on the excitation by blue light (450-465 nm). Blue LEDs (royal-blue) have this spectrum. In contrast strobes produce a dightlight-like illumination (5500 - 6000ยบ Kelvin). Wave lenghts over 500 nm (rainbow colors) must be blocked by special filters (polyester foils or dichroic-glassfilter). Aim: the blue part (450 - 480) should be transmitted only. There are 2 types of filters:

1. Polyester Foils (Lee-Filter etc.)

2. Dichroic-Glas-Filter plus special foil

The Dichroic-Glass-Filter has the advantage that it adsorbes significant less blue light than the polyester foil (40 instead of 60%). Therefore high-end strobes are necessary.

On the other hand the polyester foil is much chaeper.

 

The Cokin-filterholder allows the use of different filters. Our special construction of the filters facilitate the quicke change between white (daylight-like) and blue light. We recommend this method for comparison of targets under white and blue illumination.

In addition to blue excitation a yellow barrier filter in front of the diving mask and camera is essential to block the blue light below 500 nm.

Otherwise the fluorescence colors (rainbow colors) are superimposed by the blue excitation light.

For further informations contact me: horst.grunz@uni-due.de

 

 

Dichroic glass filter plus special foil fixed in a frame of plexiglas Cokin-filterholder can be fixed on any strobe by a velcro fastener Polyester foil fixed on Plexiglas
    contact: horst.grunz@uni-due.de

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