why top downs ?

[BlueAbyss]

I believe I have heard it is because the light comes from above, and so the pigments are more concentrated from that angle. Not sure where I heard this though, consider it conjecture.

[simplycoral]

Originally Posted by BlueAbyss

I believe I have heard it is because the light comes from above, and so the pigments are more concentrated from that angle. Not sure where I heard this though, consider it conjecture.

+1

I have heard this too. Not sure where though

Maybe we shared the same dream

[lobsterboy]

Originally Posted by fishytime

Its the way the light refracts through the glass.

Originally Posted by BlueAbyss

I believe I have heard it is because the light comes from above, and so the pigments are more concentrated from that angle. Not sure where I heard this though, consider it conjecture.

both make sense.

[whatcaneyedo]

Originally Posted by BlueAbyss

I believe I have heard it is because the light comes from above, and so the pigments are more concentrated from that angle. Not sure where I heard this though, consider it conjecture.

+2 I think it was mentioned in Giant Clams in the Sea and the Aquarium by Fatherree. But of course he was talking about clams and not coral in general.

[Myka]

Originally Posted by BlueAbyss

I believe I have heard it is because the light comes from above, and so the pigments are more concentrated from that angle.

This is why. Corals make pigment to protect from UV rays. Obviously the UV rays are coming from above, so the most pigment will be seen when viewing from that direction.

Light your corals from the side, and they will color up on that side.

[kien]

I vote for "light from above". If you inspect your corals and look at the parts where the light doesn't hit it directly (like a shaded side or the base of a branching colony), the colours aren't that great at all. At least that's the case for my corals. They go from amazing from the top, to pretty good/okay on the sides to dull and possibly brown at the bottom (undersides of branches, base of colony, side of coral not getting direct light). Anyway, that's what I notice with my corals.

[Snaz]

I would agree that corals are more pigmented where the "sunlight" hits them but a glass interface reduces the amount of light through.

Imagine looking at penny top down through one foot of water. Then imagine looking at the same penny through one foot of glass. The penny under the glass would look dull compared to the water penny.

[sphelps]

Originally Posted by Snaz

I would agree that corals are more pigmented where the "sunlight" hits them but a glass interface reduces the amount of light through.

Imagine looking at penny top down through one foot of water. Then imagine looking at the same penny through one foot of glass. The penny under the glass would look dull compared to the water penny.

Interesting logic but I'm not sure who's tank was 12" thick glass or who even has a piece of glass like that lying around to try such an experiment Glass actually has a refraction index close to water it's about 1.4 compared to 1.3, so given that tanks are generally built with thin glass when compared to the amount of water you're looking through the effects are not that relative. Try looking through glass from top down, which is often done for photography, you won't see a real noticeable difference.

The fact is, like already said, everything looks brighter and more vivid because you're looking parallel to the light source. Our vision is based on how light reflects back to our eyes and parts in direct light look brighter while other parts not in direct light are more shaded and dull. Look around outside as some stationary objects when the sun is low in the morning and when it is high in the afternoon.