Making holograms with a pen plotter | Hacker News Reader

Making holograms with a pen plotter

blog.jordan.matelsky.com

184 pointsDemiGuru26 comments

This is "old Internet" style fun territory (along the same lines as the Tom7 fun, if not quite as deep). I felt that the olive oil + fingerprint + phone screen was a really nice way to illustrate the core concept. Especially clever because it used something common and annoying to help describe how the plotter does its thing.

There are very few TFAs I upvotes before opening TFA. But with such a title, this is one of them...

Before getting further into the article I thought maybe he was going to show how to use the plotter to control the oil smearing technique, which honestly would have been kind of cool.

author here — the second I did that, I considered handing it to the robot. but ... robot with oil in my living room... I decided against it :)

thank you so much for the kind words!!

Related: ”Self Reflected” by neuroscientist and artist Gregg Dunn, https://www.sothebys.com/en/articles/self-reflected-a-giant-...

He uses the third dimension to encode time, so that you get an image of the brain that illustrates how signals propagate dynamically between brain regions.

I have a version of this on my wall and its mesmerizing to look at with the right lighting conditions

Beautiful. This needs to be an HN post on its own. Please post. I will upvote.

Done, enjoy! I posted links to his web site instead of Sotheby’s. Even though his web site is a little broken, it had much more detail on the technical process, which I think HN will appreciate.

https://news.ycombinator.com/item?id=49298723

It seems to have sunk. Sadly the window of opportunity is pretty small on HN.

omg that rocks

Related, "abrasion holography", with great good success for being hand drawn: http://amasci.com/amateur/holo1.html (1995)

Maybe could swap out the pen for a needle?

In fact, I believe that the article is describing a reinvention of this technique! Just with a plotter on oil rather than a compass on plastic.

He did it on plastic CD cases, not oil. The oil in the beginning of the article was just for explaining the refraction that happens with the ridges in the structure.

Ah, whoops, thanks!

Something tells me you didn't open the posted link.

I guess I don't know how sharp a pick with an orange handle is from harbor freight, compared to a needle.

less!

Steve Mould has a great video on youtube explaining how they work https://www.youtube.com/watch?v=sv-38lwV6vc

The 3Blue1Brown video on holograms is fantastic: https://www.youtube.com/watch?v=EmKQsSDlaa4

It would be interesting to augment the plotter with a Unimorph piezoelectric disk scanner [1], to enable finer movement so lines can be drawn closer together.

[1] https://john-alexander42.github.io/simple-stm-web-page/Disk_...

interesting! the axidraw v3 that I used for this (https://shop.evilmadscientist.com/productsmenu/846) has a 0.0125mm stepper resolution, which means that it is pretty close to not-worth-it to go any finer since the sizes of the scratches are already many microns wide. But certainly with better etching technology that would be a super cool update!

The disk is part of a larger Scanning Tunneling Microscope project.

https://john-alexander42.github.io/simple-stm-web-page/Proje...

Alexander's results show a movement range of 1.25um, 10 times smaller than the 12.5um step of your system, so in its current form it wouldn't be suitable for interpolating motor steps.

Also potentially interesting is Alexander's "cut-and-pull" technique for making scanning tips with a single atom at the point. I can't find the original reference, but here's a description:

https://www.nanophys.kth.se/nanolab/afm/icon/bruker-help/Con...

The single atom would likely immediately wear down if used for scribing, but even if it wore down to multiple atoms wide it might still produce a very narrow line? I wonder what the effects of using an STM on a photosensitive plate would be, whether the strong electric field at the tip would lead to very narrow photographic lines?

Holography is such a beautiful and fascinating gateway to physics, and it’s so rare to see true demonstrations of it. Sadly, most people have no idea what it is because of how carelessly the term is thrown around, just like in this article. At least the author admits it and provides some kind of excuse, even if it’s at the end.

William Beaty had a video of the hands on the car hood. They showed up very detailed some 20 cm under the hood as if people captured inside. Quite the find.

I've made these scratch holograms before with a compass. They're pretty fun, but very far from "real" holograms.

Chocolate is a good medium for holograms :)

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