BKtomodachi Posted March 20, 2005 Share Posted March 20, 2005 So? I think its something to do with the light refraction. For example.. heres my purple/blue crocea from above: Link to comment
FateX9 Posted March 20, 2005 Share Posted March 20, 2005 im assuming there'll be a side shot of the crocea? nice clam Link to comment
BKtomodachi Posted March 20, 2005 Author Share Posted March 20, 2005 You can see a side shot in my "shoestring" thread in the members tanks area. Link to comment
tinyreef Posted March 20, 2005 Share Posted March 20, 2005 some prismatic effect? i.e. light bending/reflective/refractive stuff? hey, i know tech-talk. :nerd: Link to comment
patio Posted March 20, 2005 Share Posted March 20, 2005 it happens to all of my pics! is there any thing i can do to prevent it?! Link to comment
apophis924 Posted March 20, 2005 Share Posted March 20, 2005 It is due to the nature the way light interacys with the clams pigments. the pigments are crystal like in nature and light reflecting off at different angles will show particular color shifts. Similar to reflect metal bicycle tape. depending on what angle the light hits it and what angel you are vewing you will see a different color. Not much you can do about it besides taking your photos from the same angle and/or changing the color of the light source Link to comment
FAC_WNY Posted March 21, 2005 Share Posted March 21, 2005 BK...do a search for "iridiophores". That's what makes the clam's color change depending on the angle it's viewed at. Generally speaking, you'll get the "best" color taking a photo from the top straight down. Cheers, Fred Link to comment
adinsxq Posted March 21, 2005 Share Posted March 21, 2005 snoopy's smart. light reflecting off the clam above tank: water->air->eye through tank water->glass->air->eye as light passes through one medium to another, it changes velocity (slows down or speeds up) and bends, depending on a characteristic of each medium called "refractive index." above the tank, the last medium to medium interface is water to air. through the tank, the last interface before reaching your eye is glass to air. light with different attributes = different visual images Link to comment
adinsxq Posted March 21, 2005 Share Posted March 21, 2005 Originally posted by FAC_WNY BK...do a search for "iridiophores". That's what makes the clam's color change depending on the angle it's viewed at. Generally speaking, you'll get the "best" color taking a photo from the top straight down. Cheers, Fred yes iridophores form the light reflecting chromophore layer in the mantle, but that's not the reason why the clam appears differently from above compared to through the side. Link to comment
BKtomodachi Posted March 21, 2005 Author Share Posted March 21, 2005 But, when I turn the clam on its side in the tank... its bluer.. just not green! Maybe both? Link to comment
adinsxq Posted March 21, 2005 Share Posted March 21, 2005 oh... never mind then i don't keep clams how do you have time to post 50 times a day? Link to comment
FAC_WNY Posted March 21, 2005 Share Posted March 21, 2005 "iridophores form the light reflecting chromophore layer in the mantle..." And we see color how again? Oh yeah..that's right...relected light. As far as the color change goes...if you change the angle of incidence of viewed light, you'll change the perceived color. Think of a clams' mantles as holograms...as you change the angle of reflection, you change the perceived color of the hologram. Same thing with the mantle. Cheers, Fred Link to comment
adinsxq Posted March 21, 2005 Share Posted March 21, 2005 Originally posted by FAC_WNY And we see color how again? Oh yeah..that's right...relected light. As far as the color change goes...if you change the angle of incidence of viewed light, you'll change the perceived color. Think of a clams' mantles as holograms...as you change the angle of reflection, you change the perceived color of the hologram. Same thing with the mantle. reflected light carries the same properties as its source, regardless of the angle it enters the eye. refracted light, as i described earlier, does not have the same wavelenth as its source. wavelength determines color (...not exclusively... there are things like color opponency that contribute). we (well most) of us are trichromats which means we have three cones blah blah blah. iridophores are responsible for the iridescence you see in clams (whites, silvers..), not the color of the flesh. the color of the clam is more weighted on aspects of light absorption rather than reflectance. afterall, why would a photosynthetic organism want to load up its tissue with mirrors? Link to comment
Steve973 Posted March 21, 2005 Share Posted March 21, 2005 I was just hoping that I could contribute (in some way) to the testosterone-fest, but alas, I cannot. Good info Adin! I always like the scientific approach. I have noticed this with my clam, though. It's teal from the top, and nearly purple from the side. If the glass slows the light down, and since purple is "slower" than blue/teal, this makes some sense. Am I even in the ballpark, adin? Link to comment
adinsxq Posted March 21, 2005 Share Posted March 21, 2005 a little more into why i'd rather accept that the layer of glass (or acrylic) as a better explanation than simply "viewing angle" to explain Steve's observation... glass (or acrylic) has a refractive index of roughly 1.5 (where air is about 1.0). a little tinkering with snell's law and we see that the the "critical angle" of glass-air is about 41 degrees. critical angle? any photon travelling through the glass at an angle greater than 41 degrees will reflect and bounce around, trapped in the layer of glass (this is how fiber optics work by the way). why is this important? light of different wavelenths travel through mediums slightly different from each other. this is known as "chromatic abberation" (and the reason you see sunsets and rainbows). light with shorter wavelengths tend to bend more than those of longer wavelength. ok, now why is THAT important? when we say "light going through a medium of higher refractive index than its source, bends more," we're actually saying that it bends more towards the perpendicular (normal). so, taking one step back, it makes sense to say that longer wavelength light is more likely to fall victim to internal reflection (filtering). if some of the longer wavelenth light is being removed from the Steve's side view (through glass), then i would expect the "filtered" compound light that results to be more weighted (skewed) towards the lower end of the visual spectrum... purple. Link to comment
adinsxq Posted March 21, 2005 Share Posted March 21, 2005 follow up on that... i guess someone out there is wondering why UV radiation does not pass right through glass. i bet it has something to do with UV giving up its energy to vibration (heat) in the glass environment--topic for another day Link to comment
FAC_WNY Posted March 22, 2005 Share Posted March 22, 2005 We need to hear from someone who has been on a dive and seen these things in the wild..lol. Then we can settle whether or not it's the glass/acrylic once and for all. Cheers, Fred Link to comment
adinsxq Posted March 22, 2005 Share Posted March 22, 2005 a diver wears a mask that's made of... X) Link to comment
nalbar Posted March 22, 2005 Share Posted March 22, 2005 i was at barry's (of clams direct) retail place a couple weeks ago the day after he went to L.A. to pick up 100 clams. his tanks are the low prop type, about 4'X6' and 12 inches tall. i was looking down into the water at 100 clams and barry goes 'look at them from the side'. i almost fainted. you think one looks amazing, try it with 100! nalbar Link to comment
supernip Posted March 22, 2005 Share Posted March 22, 2005 Im suprised you took the time to explain this. Link to comment
adinsxq Posted March 24, 2005 Share Posted March 24, 2005 i am more so that you took the time to read it. Link to comment
RandyO Posted March 24, 2005 Share Posted March 24, 2005 Originally posted by adinsxq snoopy's smart. light reflecting off the clam above tank: water->air->eye through tank water->glass->air->eye as light passes through one medium to another, it changes velocity (slows down or speeds up) and bends, depending on a characteristic of each medium called "refractive index." above the tank, the last medium to medium interface is water to air. through the tank, the last interface before reaching your eye is glass to air. light with different attributes = different visual images Actually it does not speed up or down, that is impossible, what does chage is the wave length (frequency) Light travels at a known constant. (this does not include the "bubble theory" of physics, not sure that is the proper name for it but it has to do with a vessel traveling inside a vessel. Also the theory by which warp speed travel is proposed) Link to comment
redneckvampire Posted March 24, 2005 Share Posted March 24, 2005 This is just a S.W.A.G. but could it be that the pigment in the clams mantle is sort of like the Colorshift pigments used in auto paint. There are other examples with exotic metal coatings. If I'm not mistaken they use some to coat glass windows to allow the noon day sun to be filtered more than the evening sun. Sounds like this could be a defense against the harming effects of direct noon day sun. Allowing the mantle to absorb an even amount of sunlight throughout the day. I don't know...it sounds good to me. Link to comment
Steve973 Posted March 24, 2005 Share Posted March 24, 2005 Randy, We're not talking about the actual velocity of light. We're talking about the wavelengths. "Speed" is a more convenient term, but we're talking about longer wavelengths vs. shorter wavelengths. Link to comment
Recommended Posts
Archived
This topic is now archived and is closed to further replies.