Water Baloon

[Tommy]

This is an 8x10 image planed H2 of a water balloon popping. The picture is lousy, but its a ball of water surrounded by droplets in mid-air (which hit the plate a few milliseconds later). My hand is in the upper left corner, holding a needle attached to a trigger wire.

The master was done on Harman's red sensitive plates with a ruby laser, processed in SM-6 (2 minutes). The copy was on Ultimate 08 with a coherent C315M, processed in Ultimate developer (exposed to 400 uJ/cm^2, developed for 4 minutes).

Illuminated with the sun.

[Johnfp]

Wow, that is so cool. I love seeing those in 2D. I can imagine what it looks like in 3d.

Very creative.

John

[Ed Wesly]

Hope to see this one in next year's "Box"!

[lobaz]

Nice. It would be great to have a short video.
Petr

[Tommy]

Nice. It would be great to have a short video.

Here's an mpeg file...

http://www.bobdbob.com/~tjohnson/misc/h ... _116.2.m2v

-Tommy

[rzeheb]

Tommy that hologram just blows me away. It's truly amazing. Oh to have a pulsed ruby laser!

[Kiffdino]

freaking super awesome. one of the best i've ever seen

[lobaz]

http://www.bobdbob.com/~tjohnson/misc/h ... _116.2.m2v
-Tommy

Thanks very much! Now I can see what's there. You are just a small step from this:
http://en.wikipedia.org/wiki/File:Salva ... 09633u.jpg

[ron olson]

I'm curious as to how you choreographed the shot.
Pin to pop the balloon in one hand - laser remote control in the other?
Or did you have an assistant: three...two....one....pop the balloon/fire the laser.
I assume the timing with a water balloon must not be terribly critical (what....hundreds of milliseconds for it to collapse completely?) and your laser has about half a millisecond delay between fire command and laser output. Was this the first try or the best of several attempts?
Nice job in any case. I know from experience this ain't easy.

[Tommy]

I'm curious as to how you choreographed the shot.
Pin to pop the balloon in one hand - laser remote control in the other?
Or did you have an assistant: three...two....one....pop the balloon/fire the laser.
I assume the timing with a water balloon must not be terribly critical (what....hundreds of milliseconds for it to collapse completely?) and your laser has about half a millisecond delay between fire command and laser output. Was this the first try or the best of several attempts?

I triggered it electronically...

I had a wire attached to the pin (you can see it below my hand in the mpeg) and a second wire around my other hand (holding the balloon). The pin was connected to the input of an opamp setup as a voltage comparetor while the second wire was attached to +9V (through a 1 M resistor, to reduce the shock hazard (not entirely successfully)). The theory was that when the balloon popped, I would abruptly be holding a ball of water with the needle in one side and the contact on the other and it would conduct, and fire the laser. The resistance of my hand against the balloon was actually low enough that the opamp went high just as the needle broke the rubber. So I have two test holograms of the balloon with the needle just deforming the rubber.

I then added a delay function to my laser's microcontroller, the laser was fired 20 milliseconds after the needle hit the water. I shot some video of a water balloon popping to get that order of magnitude, and then did additional test shots with a camera holding its shutter open illuminated by the laser's flash to make sure I had a good delay without burning film.

I did a lot of test shots, at least 20 water balloons, though only four holograms, two of which were duds.

Nice job in any case. I know from experience this ain't easy.

Thanks!

I've spent a lot of time reading your various web pages. Thanks for distributing your laser design spreadsheet!