Odd Lighting Question

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 ?
 

Mike

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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.
 

Warr7207

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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.
 

Mike

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

jacquesb

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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)....
 

Warr7207

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

jacquesb

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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....
 

Warr7207

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

Warr7207

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

Obi-Wan

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Nice specimen

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

If valve surface appearance matches below.
tn_shells2_jpg.jpg

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:



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 ?
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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