Structural color

[c-krebs]

One of the subjects that has always fascinated me through the microscope is the observance of "structural" color. Most of the color we see in everyday subjects is due to pigments of some type that absorb and reflect certain wavelengths of light. But there are some dramatic natural (and man-made) color displays that are not due to pigments but are caused by tiny "nanostructures" on, and in, the objects surface. These structures cause optical interference and diffraction that varies with the light wavelengths and produces the iridescence observed in these subjects. The colors can be extremely intense and "pure" with wonderful variations. You can't really get a good look at the "nanostructures" themselves with a light microscope, they are too small. The structures and the light physics involved have been heavily studied, and there are excellent SEM images that show them clearly. (Search for "structural color, nano structure, SEM" and look at the images... very worthwhile). We can however see the results. Under a microscope these subjects can be amazing.











A couple references:
http://delusions0fgrandeur.blogspot.com ... erfly.html (simple, brief, easy reading)
http://tinyurl.com/4m7fz7r (in depth)
http://jeb.biologists.org/content/209/4 ... l.pdf+html (in depth)

I might be posting some images that a few forum members may have seen it other places on the internet at other times. I apologize if you find this annoying. Let me know.

[molehill]

Fantastic images! Beautifully composed.
So is this just reflected light?
Amazing result anyway.

Molehill

[billbillt]

Good Grief!!.. I am blown away!!... These look too perfect to be real!... A am at a stammer for better words!.. More please!!..

BillT

[JimT]

Charles, so what are we looking at and with what obj. and lighting? Based on these I may have to throw away my polarizing filters

Fantastic. Fill us in on the details.

JimT

[75RR]

The impact of these very rich colours is almost a shock. Fantastic work.

[c-krebs]

Charles, so what are we looking at and with what obj. and lighting? ... Fill us in on the details.

The first two are of a jewel beetle carapace, Chrysochroa buqueti.
The third is a butterfly wing, Blue-rayed Metalmark (Lyropteryx apollonia).
The forth and fifth are wingscales of a Chrysiridia rhipheus (Madagascan sunset moth).

The first image was taken with a 5X objective, the others were taken with 2 different long working distance 20X. (Nikon 20/0.40 CF M Plan ELWD, and Olympus LMPLFLN 20/0.40)

The lighting was done with a "half-dome" white translucent hemisphere with opening cut into top for objective. (It was either a large ping=pong ball section, or the half hobby shop Christmas tree ornament I posted earlier:

The impact of these very rich colours is almost a shock. Fantastic work.

The color intensity and purity of these is unlike any color you ever see due to pigment. (Think of holding a CD so that the sun or a bright light shines on it). Normally the light incident to the surface tends to be directional, but when you use a dome like this and illuminate the outer surface all around, the light hits the subject from all directions and it is like a color "explosion". (BTW, this type of lighting, while good for these wing-scales, would be far too "flat" for non-iridescent moth and butterfly wings).

[KurtM]

I love it! This is the sort of thing that makes me want to climb out of my little box to learn about and try new things. I can think of no higher value in a forum post than that. Thank you, Charles!

This stuff reminds me of hummingbirds. Those most colorful of all birds don't have pigmented feathers, but instead reflect diffracted light to produce their trademark electric emerald greens, ruby reds, garnet purples, etc. The Ruby-Throated hummingbird doesn't actually possess a ruby colored throat (gorget) at all - it only appears so when the light hits it just right. Very magical to see it in action!

[Rodney]

Just amazing, do you have any other insect structures or insect photos you would like to share.

Rodney

[Rodney]

So that little half dome is like a little house full of light. I wonder if something like that could be made with LED lights in a half dome. I don`t have the equipment to take those kind of images but some could be usable for my little hobby.
We do have a lot of colorful insects and some aquatic forms could benefit with something like this, what do you think.

Rodney

[gekko]

Incredibly beautiful! Many thanks for the post.

[Johann]

Stunning pictures, thanks for sharing Charles - i'm pretty sure no-one will mind if they see a repeat

[rnabholz]

Fascinating subject and stunning images. Thanks for showing them.

Off to Google to read up.

Rod

[vasselle]

Bonjour
Tout simplement magnifique.
J'adore vos photos et le travail que vous faite.
Cordialement seb

[billben74]

Many thanks Charles.
Amazing....
And thanks for the image of your set up. This is help full.