Odd Lighting Question

Discussion in 'Lighting' started by Warr7207, 16 Jun 2008.

  1. Warr7207

    Warr7207

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    I just noticed today, well cleaning the top glass panes that I have a clam that I have always seen normally as Blue, but through the surface of the water it is green.

    Is this the actinic lights changing the colour ?
     
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  3. Mike

    Mike Retired Moderator

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    Is it still blue through the glass? if so then it is probably just a trick of the light, seeing it top down instead of side on through glass.
     
  4. Warr7207

    Warr7207 Thread Starter

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    It is blue through the front of the display but green through the surface of the water.

    When looking through the surface of the water I am lifting my hood with all the lighting attached.

    I will try take pics.
     
  5. Warr7207

    Warr7207 Thread Starter

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    Here you go

    Front glass of display

    [​IMG]
     
  6. Mike

    Mike Retired Moderator

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    sounds like a trick of the light then, refraction can cause subjects to "look" different.
     
  7. jacquesb

    jacquesb Retired Moderator

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    Warren - it has always been my theory that actinic lights will indeed change the coloration of corals, and possibly clams as well.... corals, clams, etc. react differently in different light spectrum/frequency ranges (the pigments that protects the corals)....
     
  8. Warr7207

    Warr7207 Thread Starter

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    [​IMG]
     
  9. jacquesb

    jacquesb Retired Moderator

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    BTW Warr - AWESOME clam man! What type is it? Looks like a derosa? Is this correct?
     
  10. Mike

    Mike Retired Moderator

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    Nice pics, cool effect too.
     
  11. Warr7207

    Warr7207 Thread Starter

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    Jacques, I would go with your ID, I have looked at my inverts book and they all look so similar. And you know how it is at the LFS - What clam species is that ? A small giant clam :arghh:
     
  12. Rory

    Rory Admin MASA Contributor

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    Clams do that... :p
     
  13. Mike

    Mike Retired Moderator

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    Yep, it looks like a Tridacna derasa clam to me too.
     
  14. jacquesb

    jacquesb Retired Moderator

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    Thanks Warr ;-)

    I think that I might be correct. The way that I was told to ID clams, is by the smoothness of the shell on the outside. Mine two squasmosa's has more elaborate "waves" and "bigger" and more protruding "kinks"..... The derosa has a more of a "smooth" shell....
     
  15. Warr7207

    Warr7207 Thread Starter

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    Thanks I keep that in mind. Any suggestions for Maxima, Hippopus and Crocea
     
  16. jacquesb

    jacquesb Retired Moderator

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    I think that the maxima has a specific coloration set - more actual greenish than blue'ish/purple'ish...
     
  17. Mekaeel

    Mekaeel Moderator MASA Contributor

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    awsome clam.the true colours of a clam are seen from the top rather than the side
     
  18. Warr7207

    Warr7207 Thread Starter

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    Now you tell me, and I wanted a green clam :p
     
  19. Mekaeel

    Mekaeel Moderator MASA Contributor

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    lol.try and keep him in a slant,maybe you will beable to view the true beauty of the clam better
     
  20. Warr7207

    Warr7207 Thread Starter

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    Tried it at different angles. if viewing through the tank's glass it is purple/blue, soon as viewing above it's green.
     
  21. Obi-Wan

    Obi-Wan

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    Nice specimen

    Tridacna crocea......you got there Warren.

    If valve surface appearance matches below.
    [​IMG]
    Side view of typical crocea valves.

    I have had MANY Tridacnids.

    T squamosa
    T derasa
    T maxima
    T crocea
    STILL have a few dozen hidden all over the place! :biggrin:



    Switch your actinics off, it will STILL appear blue-purple and green from front and top respectively.

    It's the different REFRACTIVE INDICES of MEDIA SUBJECTED TO light passage on the way TO YOUR EYES.

    Light from LAMP > air > water > clam mantle

    RETURNS VIA >water
    THEN EITHER through

    ~ glass > air > YOUR EYES!
    ~ air > YOUR EYES


    refractive Index = measure of how light "bends" passing through different transparent/optically transmitting media with different refractive indices.
    It's SPEED AND ANGLE is affected. Apparent position, colour may appear altered.

    Everytime change happens, wavelength is altered. It SO happens, for your clam viewing, that deviations lead to wavelength sufficiently different, to appear as another colour.

    Recall ROYGBIV, as spectral make-up of WHITE LIGHT colour-wise?

    Can you See CLAM shifted colour through LESS refraction from top will be GREEN ?

    Larger deviation through glass will shift apparent colour to BLUE-INDIGO-VIOLET

    Very shallow tanks, or tanks with slanted viewing panes capture the colour YOU want it to display for YOUR OWN aesthetics.

    I have a bank of shallow (225mm) tanks for clam and frag holding and experiments.
    All specimens were in natural sunlight, supplemented by actinic, if needed.

    I learnt ALOT .

     
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