Rock Disco videos

[microcosmos]

I'm starting on a series of videomicrographs of petrographic thin sections being rotated in cross-polarized light to illustrate their birefringence colours and extinction angles relative to their crystal faces/cleavage.

The video above shows a sample from Tambora volcano, the site of the greatest eruption in recorded history in 1815.

Videos like this have been done before for educational purposes in optical mineralogy, but not at such a high speed of rotation and not precisely cut at the exact frames to give the impression of smooth and continuous prolonged rotation with looping.

This is why I call this series Rock Disco, as the light effects can actually be used in a disco. I feel that microscopical imagery, beyond being informative and beautiful to microscopists, could actually cross-fertilize other sectors such as graphic design, fashion, interior design and entertainment.

[microcosmos]

Here's another one at more than twice the rotation speed of the previous video (0.7 revolutions per second versus 0.3), a noritic-gabbroic rock with less fine-grained groundmass and a mix of grey plagioclases and coloured pyroxenes.

Actually it's a bit too fast this time - the colour changes in the outer parts are too blurred out. I just wanted to see how fast I could spin the stage while maintaining a steady speed. I used 24 fps to get the characteristic cinematic effect on fast-moving objects.

It helps in composing the shot if you have a crosshair graticule and your objective/stage is centred to the crosshairs, so you can precisely position the axis of rotation at the desired point in the sample.

[microcosmos]

Apologies - I just realised the videos don't load in Firefox although they do in Safari which is a bit smarter when a video has an image tag. I haven't tried other browsers. Sorry if you can't see them!

[smollerthings]

Hi microcosmos,

I can't wait for Rock disco to happen. I can't see any of the images or videos you posted on this thread.

[microcosmos]

I'm sorry I don't know how to make it work - the only way is if you visit this website using Safari browser, either on a Mac or an iPhone. Then you can see it.

In Safari, if you embed a video inside an image tag, it will automatically play the video without sound and continuously loop it, making my Rock Disco rotate continuously, forever. The advantage of this is that the actual video is only one second long so the file size is really small, and there's no sound to disturb anyone.

If I embed it as a normal video, it will only play for one stage rotation of 360 degrees and the disco effect is lost.

[smollerthings]

Works on my iphone indeed. May I suggest you loop it and put it on Youtube? It will be easier to embed it this way.

Colors are wonderful. I prefer the slower version. Actually even slower would be good, albeit not as "disco"

[microcosmos]

I'm glad you enjoyed it! I looped it 10 times and uploaded it (not on youtube but on the server I use for my website).

Now I realise I can't directly embed the video unless it's on youtube. Oh well. Here's the link to watch it for those who wish to. [Edit: this link is no longer valid. I have switched to youtube - see the playlist here instead.]

I prefer the slower one also, although I wouldn't want to slow it down any further because it will begin to look like an optical mineralogy video rather than a disco as you said.

The quality looks very poor on my retina screen because it's just HD to begin with, and then it displays the video as if it's on a lower-resolution screen instead of using the actual pixels of the screen. It drives me crazy that the Mac OS does this and leaves the user (not a computer scientist) frustrated trying to figure out how to force it to display the video at actual resolution. I can do it by using html code to specify the size at which to display the video, but that is if the website allows me to code in html.

I think I'm done with videos for now. The only interesting thing I can do with the samples I am studying currently is to rotate the stage like a disco. Maybe next time when I study something that is more amenable to video.

[Rossf]

Very cool microcosmos -whoever says “disco sucks” is a fool! Are these transmitted light or reflected light? If transmitted light are they semi opaque or quite see through specimen?
Regards ross

[microcosmos]

They’re transmitted cross-polarized light through 30-micrometer thin sections of rock, which are almost completely transparent.

The microscope slide looks like this:

166339CC-EC72-4A74-B95C-C653D1F64F89.jpeg (97.92 KiB) Viewed 2583 times

Try playing the video on a big screen in a blacked-out room with disco music!

[Rossf]

I can personally concur it works well with RuPauls’ “Stinky Dinky” from his/her first album…

[microcosmos]

I had a listen to Stinky Dinky. It works! The siren is a nice touch - it goes perfectly with the lights going on and off in the video!

I decided to give the two videos a proper home in this playlist on youtube.

Thanks for all your interest and hope they come in handy if people ever need some lighting effects for a microscopy-related party.