Why do Diatoms lose color when switched to higher Objective

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Sam236
Posts: 57
Joined: Sun Sep 22, 2013 1:39 pm
Location: CA USA

Why do Diatoms lose color when switched to higher Objective

Post by Sam236 »

HI,

I have several diatom slides that are very colorful at the low magnification, like 2x and 4x. the color start to disappear when I use 20x and at 40x diatoms lose all the colors. is this b/c increasing the intensity of the light? And is there anyway to retain the color of diatoms at the high magnification?

Thanks, Sam

Pau
Site Admin
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Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

Sam,

The "diatoms" in the typical mounted slides aren't the whole cell but only its amourphous silica frustula. In fact they are colorless. The nice colors you can see with low power magnification objectives in some species are due to interferences of light in the fine punctae patterns not well resolved by the lens (a phenomenon perhaps comparable with Moire false colors). With higher NA typical of higher magnification objectives as resolution increases the phenomenon dissapears.
May be a bit frustrating but it is normal.
Pau

Sam236
Posts: 57
Joined: Sun Sep 22, 2013 1:39 pm
Location: CA USA

color

Post by Sam236 »

hi pau

thanks for the reply. learned something new.

Sam

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