Handmade holograms are really weird

[@SteveMould]

At no point did I mention that the light source needs to be small and bright. Which is strange because the light source needs to be small and bright. The sponsor is Incogni: The first 100 people to use code SCIENCE at the link below will get 20% off: incogni.com/science

[@spidunno]

ah

[@username4441]

whats it like just experimenting and having fun for a living and having a loving family?

[@vaibhavbv3409]

Nice deceptive thumbnail

[@rocketboysmc]

to i? did you mean do i it appears to be fixed now.

[@rand0mc1tyz3n8]

I couldn't find the links in the description 😕

[@JollyTurbo1]

That opaque square was trippy. I'm sure I've seen holograms that do the same effect, but this was on another level

[@SpydersByte]

yea that worked surprisingly well

[@chrisd1746]

The fact it was done by hand is just mindblowing

[@Flopsaurus]

Which opaque square?

[@SpydersByte]

@@Flopsaurus the one with the S behind it

[@richardmellish2371]

If all the objects are made by scratches, how does one object hide another one?

[@rich9965]

As a kid in school back in the 70s one of the other kid's brought his mom for show and tell. She worked at a tech company, i think HP, and she brought in a few holograms she made with a laser on large sheets of acetate. I recall examining them closer and noticing they had all these swirling textures to them up close. Amazing to finally have the answer to a question in the back of the mind answered over 40 years later!

[@minx8334]

Never thought to ask ur mom?

[@rhettlee]

Deep cut memory. Love solving those deep seeded mysteries. We need a word for nostalgic mystery solutions.

[@danielkoga9937]

Laser etched holograms are not colorful on pupose. They use two physical effects: light interference and fine grating diffraction. The point is to etch a reflective (or absorbitive) surface with points that will interfere in our eyes so each eye sees the same image, but "dislocated" by the 4cm each of our eyes are separated.

[@thephoenixsystem6765]

He's doing God's work!

[@Xaddre]

I did this on a school metal toilet paper holder like 5 years ago. (For reference I have lots of experience making this kind of art) I put my name on it like an idiot. When I inevitably got called down to the principals office he wasn’t even mad about it he was just curious how I did it. So I showed him and after he asked me to make something for the school art show. I was given sheet metal from the shop class and I carved the schools logo into it. It wasn’t my greatest work, but for me at the time it was really good. I added my signature behind the logo so you could only see it from a specific angle. Also if you vary the line angles of different objects you can create 3d images with foregrounds and backgrounds. This is my favorite kind of art as you can create a 3D landscape in a 2d sheet. I also have messed with adding some color into the scratches on the surface of the image to give objects different colors.

[@FrostshadowStudios0310]

Easily the most impressive thing I've ever heard. By far the best😁

[@konstantin7596]

@Xaddre Did you do that all by hand, still? Or do you also have some cnc machinery at home? How are the colors added, by different scratch depths? In some kind of CD-like surface? Really cool!

[@xantiom]

He said he did it on the toilet, he clearly did it by hand

[@wbeaty]

If you have some carbide powder, you can sweep your hand across the mirror in the mens room. Sweep in a broad curve. If there's a small spotlight shining on it (and not fluorescent tubes,) you'll see a glowing 3D handprint down inside the mirror. Or, with a leather-covered block and a woodburner, you could make the school logo, then use carbide powder to put it into all sorts of polished outdoor surfaces (with sunlight to illuminate.) Back in 1994, I was imagining using this to make Virgin Mary or Elvis patterns, then charge money to all the people wanting to see the miraculous image. (Can't do it today. Everyone now knows about scratch-holography!)

[@BestCrafting]

Finally a piece of content that actually uses the cross-eyed stereogram. It has always felt useless, aside from solving ‘find the difference’ challenges, but now I’ve finally used it again haha

[@mikeuk1927]

OMG I'm not the only one that used this trick to slove the 'find the difference'. It really messes with people who don't know how you did it :)

[@NickiRusin]

It's really extremely effective for that. I also used it a while back to find differences between a bunch of text in Word documents, but my head did hurt for a while after that

[@eugenetswong]

I never thought about using them in those challenges. Thanks!

[@thewiseturtle]

I put a stereogram on the back of one of my books I publishes. I doubt that anyone else even figured it out, let alone appreciated it, but I love it.

[@richardpike8748]

@@thewiseturtle I'm sure someone like vsauce down the line will eventually find what you did and be like "this person was cool"

[@gingermany6223]

I remember reading about this technique in a science magazine 20+ years ago. The author of that article mentioned seeing this effect in the paint of a black car where a hand print seemed to be floating where the same hand had wiped the surface with a cloth but from two elbow pivot points.

[@hakajiru264]

Same, I think I read about it in a science magazine from the 80s or even older.

[@walterriblethegreat]

I read that article, too! I think I still have the hologram I made years ago on a CD cover using this technique...

[@SteveMould]

I'm pretty sure that's Beaty that I mention in the video. He talks about a floating hand print somewhere on his website.

[@statusquofugitive8554]

@@walterriblethegreat i tried it on a cd as well when I was a kid but my compass sucked and the hologram was pretty weak but still cool.

[@mathematicalsarthak]

​@@hakajiru264a

[@fideliareeve3493]

I'm blind in my right eye so when you started talking about the glint in a dirty windshield or the pot lid looking further away at certain points my mind was blown. I've never experienced that and never expected it was such a different experience for people with both eyes. It's always just been a glare to me. A smear. Never thought anything of it at all. I don't usually think much of being blind in one eye as it's all I've known but sometimes I get sad there's stuff I can't experience no matter what I do.

[@clonkex]

My mum's blind in her right eye as well. She calls us weird when we talk about seeing two fingers when you hold one up close in front of your face lol. For a few years I've really wanted to find a solution for people who are blind in one eye to be able to experience 3D sight. I keep wondering whether it might be possible for your brain to interpret overlapping images from one eye as 3D if those overlapping images were adjusted for where you were looking. One day I'll try it out. It would be difficult, however, because you'd need accurate eye tracking and very low response times. On the other hand, if it worked it might make returning to regular monocular vision seem really boring and flat, so there's the potential for making things worse haha. On another note, it only recently occurred to me why mum doesn't find reflections in the TV nearly as annoying as we kids do. Because of course, with binocular vision, we get the impression of the reflection being further away/not on the same plane as the TV screen. Worse, each eye sees a different image, which makes the image tend to "shimmer" and be even more annoying. It's the same effect when I'm trying to look at something up close that's reflective. I have to close one eye to get a clear image because each eye sees a different image and it's impossible to see anything clearly.

[@chaos.corner]

To be honest, I've never really paid attention to it. I think it's probably one of those things you get used to almost immediately unless you're actually looking for it.

[@Ramdapanda]

​@@chaos.corner yup, same

[@doctorpc1531]

@@clonkex Probably easiest would be to try this with a VR headset, somehow superimposing the images intended for each of the eyes to both just hit one eye

[@clonkex]

@@doctorpc1531 Yep, that was a thought I had, but I don't currently own any VR headsets with built-in eye tracking and I wasn't confident enough with the idea to spend money on an eye-tracking addon. Plus I already have enough uncompleted projects to last me a lifetime lol

[@0FG0]

Sitting here cross eyed watching holograms and then AHHH two Steves!

[@n16161]

lol sameeeee

[@saemstunes]

😂😂😂 Yes! That was a funny moment

[@akiradkcn]

He forgot to change his Minecraft skin

[@DontMansion]

I developped VR app for training crossed eyes for myself

[@TOMPOV]

same

[@JamesTM]

This makes me incredibly tempted to write some software to generate a CNC path that makes these. *Edit:* Not 30 seconds after I posted this, you explain that's exactly how the professional one was made. :joy:

[@richardpike8748]

engineering minds think alike :P

[@Topy44]

Haha, I just had the same thought exactly, or rather on how to build the CNC machine.

[@aaa303]

Once the software is created, would it be expensive to generate the etchings? I was wondering if they offer any for sale, but it doesn't look like it.

[@Koushakur]

@@aaa303 Depends a lot on how much big acrylic sheets like that costs, and the time spent on logistics of buying material, manufacturing and selling. So in short, 'maybe'

[@pchris]

@@aaa303 If such software for generating G-code for something like this existed, I would totally convert my 3D printer to have a knife or some sort of etching tooltip instead of a nozzle to make something. I hope James or someone actually makes software for this that is publicly available.

[@nenelan]

Never had good luck with the stereograms. Monocular vision really screws with that! But those holograms are FASCINATING! Just scratches and shiny, who knew!?

[@bermchasin]

same. it just doesnt work for me no matter how hard i try

[@nenelan]

@@bermchasin I have to force myself to pick which eye to focus from. Optometrists my whole life have not really been able to offer much in way of assistance. Lasik they said would not take care of it, and a 2-3 year patch over the stronger one MAY help the other compensate. But, not worth the headache.

[@zackbuildit88]

​@@nenelan wait, does that effect depth perception, if you can only be effectively using one eye at a time?

[@nenelan]

@@zackbuildit88 Correct! I have none. Sports in school was always a challenge.

[@brown297]

@nenelan I'm the same. I've had monocular vision for as long as I can remember, I went through years of specialists when I was younger and I did the patch which did nothing. Lasik was one of the best things I've ever done, but that was probably more because I had 2 different focal strengths (I was born short sighted in one eye and long sighted in the other). I have "trained" myself to have depth perception by using my environment and referencing known lengths of different objects, but in open spaces it all goes - best example was when I saw the grand canyon and it looked like a flat painting

[@Krail1]

Thank you for this! I'd heard several times that if you break a holographic plate in two, both halves will still have the complete image, just limited by viewing angle. I've been researching how holograms work, trying to wrap my head around how this could possibly be true. Watching this video (and comparing it to the shine lines you see on a windshield or a pot lid) finally gave me an idea about how that might work.

[@Quantris]

I don't know if this helps or makes it more confusing but one way to think about it is to compare it to looking through a window. If you cover most of the window leaving just a small hole to look through, you can still see the whole scene outside if you get up close to the opening and look through it at different angles.

[@Krail1]

@@Quantris Yeah, I'd heard that idea before, but it didn't really help me wrap my head around things. Like, the light from a window is all coming from somewhere else, and that doesn't help me conceive of how an entire scene can be recorded on every point of a surface. I guess it helps visualize a little bit how it's really just one very specific angle of said scene on each point.

[@JosephsDesign]

I noticed this same sort of effect on scratched shiny surfaces like a car or counter. There are tones of random scrapes in all directions, but when light is shining on it the scrapes appear to be in a circular pattern around the light. It’s a really cool phenomenon and I never new you could do so much with it

[@jt12blk]

As soon as I saw the thumbnail and title I thought “Bill Beaty described this on his amateur science web site.” Glad he got a mention! Very nice explanation in this video.

[@BryanWLepore]

I just tried it on an old CD "jewel box" case and it works! Amazing! So easy, yet so fascinating!!

[@scififan698]

Great hobby with the kids, ey!

[@georgH]

Thank you so much for the cross-eyed 3d images, they were wonderful! I usually use this technique when photographing scenery or objects where seeing the actual depth makes a difference.

[@DaedalusCommunity]

I did not know that was a thing, I'm astonished right now

[@oezzimix]

@@DaedalusCommunity takes a bit to learn, but it's rewarding once you got it down.

[@DaedalusCommunity]

@@oezzimix for me it sort of clicked instantly, i crossed my eyes and they immediately locked on the picture, blew my mind

[@oezzimix]

@@DaedalusCommunity nice!

[@batgwill]

I have never been able to make the cross-eyed 3d thing work for more than a split second until this video. For some reason, i was finally able to hold focus on the “center” image. Every other time it would pull out of focus, but for the first time it just snapped in and i could see it without straining. Thanks Steve!

[@ReySilverskin]

I can never see those cross-eyed stereograms, but I'm really good at the other kind where you de-focus your eyes until the images overlap. Thankfully that technique still works on the cross-eyed kind; it just ends up looking inside-out, with the "near" bits appearing "far" and vice-versa.

[@fredericapanon207]

I defocussed my eyes for those etched stereograms. They still worked.

[@nonwibb]

It should be somewhat easier for cross-eyed, since with parallel stereograms there is a maximum separation possible (unless you are somehow able to point your eyes away from each other). Just look at your finger and bring it closer to you as you focus on it. Then do that same muscle movement without your finger. It's how to go cross-eyed.

[@throughcolouredglasses9300]

WAIT. so the reason americans say to "go cross eyed" to see these is because YOU'RE ACTUALLY SUPPOSED TO?? Omg! I'm from Germany and the only ones I've ever encountered are the kind where you have to unfocus your eyes. It's always explained as "staring *through* the image" Watching this video i was kinda confused why it was harder to get the image to work than what I'm used to! Guess I'm rewinding and watching again, going actually cross eyed this time

[@nonwibb]

I think the people having trouble doing cross-eyed stereograms are just watching this on their phone, and when something is right in front of you its hard to do. And parallel view sterograms are impossible on a computer screen because it's too big.

[@ruthrisberg4632]

@@nonwibb I have been able to point my eyes away from each other as long as I can remember. But I think I've only found how to make one of the move-eye-inwards-muscles relax. I essentially disable they autopilot for making my eyes a suitable distance from each other where I don't see double. So even though I can control my eyes pretty well, my manual controls are far from the accuracy we have evolved to use instinctively. This means that they keep moving ever so slightly towards/away from each other even when I try to keep them still using this method. (When I don't do anything they work like eyes would normally do.)

[@PopeGoliath]

1:20 Ack! Two Steves!

[@alzandermuller]

Very cool idea to show the 3d-ness via stereogram 🙂 loving the content!

[@deadfishyarou]

@chuharry5360 perhaps obvious but way underutilised

[@alzandermuller]

@@deadfishyarou if it were that obvious, everyone would use it 😂 Definitely underutilized though

[@PhilBoswell]

This is how snow, or an icy road, sparkles: you get reflections off different ice crystals that your eyes interpret as matching, so your brain thinks there's tiny random sparkles of light at various distances including inside the surface of the snow/road/whatever.

[@jakefriesenjake]

There's glass in some pavements.

[@plixplop]

Similarly the reason cat eyes look surreal at night - the cat's two eyes reflect the light source slightly differently back to your two eyes, causing a scintillating 3D effect which tricks your brain that the glowing eyes are almost hovering in front of the cat's face.

[@heyspookyboogie644]

Glad you incorporated the cross view stuff. That’s the only way I can see 3D images but since more people are used to the magic eye way, it’s rare for people to do that.

[@williambarnes5023]

You can do this with color too. Use three transparent plates on top of a black backing. Etch each one wherever its color appears, and etch more deeply where it's stronger. Full color hologram.

[@thedofflin]

I was literally about to say "Wouldn't it be mad if he gave some side by side footage so we could see it cross-eyed" and then you bloody did it, this is why I love your channel.

[@BrianPletcher1]

Experimented with this for my science fair project back in high school in the 90's, and ended up getting to go to the international science fair! Very neat stuff, the CNC version is awesome.

[@michaellabrador2549]

Maybe a clear acrylic with a point of light shining down through it from the top would mitigate the distortion and also make a nice glowing hologram.

[@fatcat1414]

This was actually really helpful for me as an artist to better understand how reflections work. Thank you :)

[@simonabunker]

Not quite an interference pattern, but this does seem worthy of the "hologram" name - unlike all the Pepper's Ghost projections you see advertised as holograms. Love the way you can peek around the front etching!

[@AndrewTaylorPhD]

Something like this happened to us once - there was somehow a scratch in my dad's car that appeared to hover about an inch above the surface. It was very strange to look at

[@dave7038]

Sometimes you'll see this in car paint when someone wipes the dirty surface with a towel. The grit acts like fine sandpaper and creates a scratch hologram of the towel. If they have their hand flat on the towel the hologram will encode an image of the hand with scratches of different depths corresponding to areas of higher pressure, so you get a kind of grayscale image of the hand. I'd suppose it's possible to machine a hard surface with a depth map of an object, pour soft silicone onto it, then use the silicone cast with a fine abrasive to etch a hologram with a strong grayscale effect.

[@ptarmigan1356]

Using stereograms in the video is such a cool idea! Sadly I can only do wall-eye ones, but it was still cool for the simpler ones- for me the smiley was just above the surface instead of below. Might take this as an opportunity to try one more time to learn to see cross-eye stereograms

[@smilerbob]

Really enjoying the cross eyed stereogram and then without warning…two Steves appear! Some things in the universe shouldn’t happen 😉🤣 Great video as always, thank you 👍 I have always found holograms, or light refraction and reflection, fascinating. Could be my autistic traits showing through

[@benwisey]

It would be good if there was a video with just the cross eyed stereogram bits.

[@neopalm2050]

or perhaps a quantum superposition of one Steve in two places

[@smilerbob]

@@neopalm2050 In which case Steve wasn't anywhere while he was making the video 😉

[@cyanoure]

Me too, I like these 3d videos.

[@scootermom1791]

No, it's not your "autistic trait," silly. Many people find this fascinating whether they have autism or not.

[@ODISeth]

Interestingly Steve, you mention how the side-by-side video clips work well when you go cross eyed, but I was curious how the clips would look when opened in VR. It looks STUNNING, and the illusion is far more clear and comprehendible than it is when just looking cross-eyed at a flat screen. And that got me thinking, you’ve made your fair share of stereographic clips across a few videos on your channel, have you ever thought about making an entire stereographic video intended for VR? Whether it’s something new and unique or just a compilation of all the clips you’ve made in the past, I’d be fascinated to see what you do with the technology

[@kaigorsuch3586]

I really appreciate the cross eye stereographic 3D parts of the video! I would much enjoy if other creators did the same with things that depth would enhance. nice one!

[@PosyMusic]

Awesomeness. I never knew it worked that way!

[@plixplop]

You might also look into "anisotropic highlights" which is the general type of "light-perpendicular-to-a-tube-shape" based highlights we are seeing here.

[@Prefesuersheen]

I had 4:19 happen to me once, although it was caused by ice that I suspect had kept getting frozen, defrosted and smoothed because I didn’t know how my defroster worked and it was extremely cold outside. It was gorgeous, every light source- tail lights, reflections, the moon- made this magnificent 3D arching into my view. It was dangerous to drive with, but I wish I could see it again. Thanks for highlighting that phenomenon

[@MrSupahlovah]

i found william beaty's page years and years ago, forgot about completely, saw the smiley face and immediately remembered it!

[@Emariess]

oh man wbeaty is such a youtube throwback. used to watch his videos like almost 15 years ago! crazy.

[@RoyWiggins]

Beaty's been in the biz longer than KZbin, his website blew my young mind two decades ago

[@wbeaty]

@@RoyWiggins Someone discovered that Charles Wheatstone almost invented scratch-holograms. He was examining lathe-turned disks under candle light, noticed the 3D stripe, and it led him to invent stereo (first the hand-drawings, later photos and the stereopticon.) We almost had Victorian Steampunk holograms.

[@NonEuclideanTacoCannon]

My dad showed me how to do this when I was a kid in the 80s. He did some really freakin' cool ones. He tried to do laser holograms too, but he never got it working right.

[@darketsdort]

You should try it out

[@djkor]

Crossing my eyes trying to get the first smiley face to go 3D and not having much luck "fine tuning" it, then you put the next one up and all of a sudden everything is in excellent 3D.

[@LewLaps]

I absolutely love the crossed eyes stereoscopic images, it's so so so cool to see new ones!

[@olneydetail1487]

As a car detailer this is a great explanation of what paint marring and damage is plus concealing the the paints true luster, gloss and deprh behind holograms.

[@lordofmorgul]

Ladies and gentlemen, I think we might finally have a Parker cube.

[@SteveMould]

It makes me so happy that you're proposing "parker cube" not "mould cube"

[@nahometesfay1112]

@@SteveMould even when it's not Parker's fault we all know deep down it's still Parker's fault

[@lordofmorgul]

@@SteveMould I wouldn't feel safe yet, "[insert name] tesseract" is still not taken.

[@carubylachhiramka6072]

​@@nahometesfay1112 haha

[@SpaghettyLuvsU]

Thanks so much for doing a _cross-eye_ stereogram! I see so many videos that swap the eyes so it works like a Magic Eye painting, and I just can't focus far enough "past" the monitor to get the images to converge. This way is much, much easier!

[@samdann5366]

The Visa Dove is not an etched hologram. That was created using a model and a holographic camera. The dove was scupted in clay and cast in plaster or epoxy. I know this because my father was the sculptor who made the dove for Visa. He was one of the top sculptors working during the hologram craze of the 80s and 90s and worked for such companies as Kenner/Hasbro, Marvel Comics, DC Comics, Lucasfilm, Mattel, the NFL, American Bank Note, the Danbury Mint, etc.

[@wbeaty]

The Visa Dove IS an etched hologram, a "surface hologram," composed of hundreds of thousands of microscopic reflective lines. But the lines are produced via optical interference, not by abrasion. The Viza dove is a Benton white-light hologram. These scratch-holograms are also Benton white-light holograms. The physics is the same for both, and that's the key to understanding them. In 1994, I originally invented these when I realized that, since Benton holograms are frequency-independent, this requires that the fringes in the Gabor zoneplate be size-independent. The fringe-spacing is irrelevant, and plays no role in 3D image-reconstruction. Therefore, we can draw real holograms by hand, with a sharp needle, but only if the holograms are of the Benton type, featuring only horizontal parallax. In a Benton "rainbow" hologram, if we increase the fringe-spacing to millimeters rather than microns, the hologram still keeps working, although it does lose the rainbow-banding artifact. Or said differently, the Viza Dove is an example of producing the tiny reflective lines of a "scratch hologram" by optical methods, rather than by surface-abrasion.

[@samdann5366]

@wbeaty *Visa. You invented Benton white-light holograms? Wow. So, as I stated above, it's not a hand etched hologram. If it were there would be no need for a physical 3D object. Why use an extra step with a physical object when a computer graphic or illustration could be used instead? A 3D object hand-sculpted by my father. He did 100s of them in the 80s and 90s. They were cast in epoxy and shaded by airbrush.

[@QwertyAD1150]

Couldn't do the cross eye thing, used my vr... Worth it.

[@MadScientist512]

Automating these with laser engravers or CNC machines should bring a whole new dimension to custom decorations. :)

[@sleuthelle]

Depends on the material I think. It needs to be a clean scratch, and laser engravers vaporize plastic leaving a white line and CNC machines tend to be very rounded so it may work but I don't know for sure

[@ChrisJones-xd1re]

The eggface made of scratches works fine but there's something wrong with the turquoise ball on the tiger striped background

[@macronencer]

I was thinking that for manual holograms with dividers you could plan a 3D image by printing out a sheet of paper for each arc radius, and setting the dividers correctly each time you followed a sheet. You'd need a way of registering them so they were in consistent positions - perhaps a peg system such as animators use when drawing by hand?

[@SteveMould]

Nice idea

[@dirtpoorchris]

That's so crazy its almost like a glimpse into the hidden order of our universe. How quickly you can turn every point into an arc and then use light to transforms the arcs back into a representation of the original picture...

[@allNicksAlreadyTaken]

Someone should make a program that gets an input of dots and generates a list of instructions on how to create a manual hologram that depicts those dots. Kind of tricky to define occlusion though.

[@Joshuahuk]

It would take a very kind person to go to all that effort and release it for free. I'd be interested to buy it if someone does want to make it though! Or we could ask ChatGPT 👀

[@KallePihlajasaari]

It just needs someone to make a crude attempt using popular coding tools and uploading to git hub and letting other random internet strangers slowly improve the code until it is as good as opensource 3D-printer slicer programs. I think a RepRap with a 500mW laser might be able to scribe these marks into a sheet of plastic.

[@KOZMOuvBORG]

2:43 while viewing the stereograms, found that placing my finger before the screen and moving it back towards your eyes until each side lines up helpful to sight in.

[@StopChangingUsernamesYouTube]

On the "damn I just don't know if any hobbyist can pull off that resolution" end, I bet a pattern could also be etched into a PCB. _Might_ be a pain to get that fine of a masking layer using any hobbyist processes, even before getting that perfect etching time comes into it.

[@jnbsp3512]

fun fact, etch holograms can be transferred to *chocolate* quite ok. You just need to make a negative out of a durable food safe material ;)

[@KallePihlajasaari]

If the groove is a smooth round bottom one then the inverse of it will be a smooth ridge, this will give a slightly BETTER result as the smooth curved potion is not recessed. However a raised surface is more vulnerable unlike a groove.

[@Scribblersys]

I wonder if you can stamp a CD out of chocolate

[@KallePihlajasaari]

@@Scribblersys Hmm, Hypothetically possible but might not work with the regular master mould/stamper as this makes the pits into the BACK of the disk that are read THROUGH the plastic with the silvering (aluminium) on the stamped side that is then varnished for protection and to allow printing. For a chocolate disk you would have to use a unvarnished CD as a stamper and then aluminise the chocolate (might be tricky to reach adequate vacuum) and offset the disk so that the CD player would find the reading layer at approximately the right distance from the reading head. Protecting the delicate surface from dirt and scratches would make the disk very vulnerable.

[@jimmerseiber]

Your ability to explain this in a way that anyone can understand..all of your videos.. thank you. You have a gift.

[@NorthOfEarthAlex]

You should use a Cricut to print the etching. That way you can use a digital design and make something complicated.

[@peadarwagon]

I love how many times you build working models from 3D to 2D to help illustrate how they work, and this time you literally take a 2D object and create the illusion of 3D

[@kapilbusawah7169]

Bro, that stereoscopic effect was mad! It was legit real! Plus it looked way more HD as well! Please make more of these, that was so trippy dude 💪🤙🤙🤙

[@Captain_NeL]

I really love you videos. Every time I see your smiling face I think "oh, something new and interresting is commin', that will make us better"

[@TwoScoopsOfTubert]

I want to make things now. What about the "traditional" hologram? How does it differ from what you're talking about here? Great stuff as always

[@neopalm2050]

Those go as far as making the light interfere at the level of the wavelength to make the hologram genuinely indistinguishable from if the actual thing were there. With these, your lenses still focus at the depth of the surface, even if your eye-seperation-based depth perception disagrees. With traditional holograms, even the lens you'd use to focus the image is the one for the image's depth rather than the surface's depth.

[@1224chrisng]

the Thought Emporium made a video about making them, it works using laser interference on a piece of film when you make the film, you split one laser into two, send one into the film directly but reflect the other off the object, this exposes the film with an interference pattern, which is basically Interference = Clean laser - Object laser. When you want to look at the film, you shine the clean laser onto the film, and Clean - Interference = Object laser

[@1224chrisng]

@@neopalm2050 does this mean that this video's hologram is basically a fancy stereogram?

[@barneylaurance1865]

@@neopalm2050 Why does your lens still focus at the depth of the surface with these? Binocular vision depth-perception and focus depth-perception are both about parallax effects, it's just that binocular vision uses the distance between your eyes, and focus uses the distance between different sides of the pupil of one eye. Even with one eye closed you still perceive things from different viewpoints, those viewpoints are just close together as they are all within the one pupil.

[@neopalm2050]

@@1224chrisng No. A stereogram is just two images, which need to be interpreted as a 3D thing by your eyes. A true hologram gives you an entire light field, which tells you everything that can be known about the light at the panel at which the hologram is displayed. As I said, you'd use lenses with different focal lengths for each case. Also, if you look at a stereogram from a different angle than the one you're supposed to, it will look distorted, while for a hologram, you have total control over the image at every angle (up to the diffraction limit (I think?)) if you can find a way to produce such a hologram. As for the things in this video? I'd put them somewhere between stereogram and hologram. They give about as much control over the image from a human standpoint as a hologram would, but they don't actually give a light field at all.

[@Raylative]

Matthew Brand is a genius, im blown away

[@jesseshort8]

I always look forward to these videos, they never disappoint.

[@williamchen454]

Wow I’ve been alive for so long and never really appreciated that I’m seeing double in the background and not just stuff out of focus

[@FreshPe]

8:45 Is the code for turning the 3D model (of blender) into CNC code (I guess gcode) publicly available?

[@nrdesign1991]

I saw this exact technique demonstrated on a website many many years ago but never got any results myself. Your explanation makes perfect sense of this.

[@NitronF117]

I enjoyed the stereogram bit… but maybe next time, let us know when it’s about to end… it was slightly painful to have my focus changed so abruptly.

[@username4441]

liam get boo boo? need milky bottle?

[@NitronF117]

@@username4441 what is your goal here?

[@sandasturner9529]

@@NitronF117 don't bother. The commenter just wants attention. Ironic, right?

[@NitronF117]

@@sandasturner9529 It’s certainly possible. I try not to assume the intentions of others.

[@KallePihlajasaari]

@@NitronF117 It is odd that people complain about something that is inevitably going to happen. You are commenter number 3 out of 2000 to be upset but the abrupt end of the stereo portions. Others took it in their stride and laughed about how there were two faces to replace a stereo view or a scratch hologram. So perhaps User Name is a troll but in a sense you are too. If you practice with stereograms you get used to the non-standard eye movements and it is just one blink and you can reset to normal by looking at a familiar object. Try it again with this video if you want to practice. Offer the advice to others that are struggling.

[@enphc]

this is really interesting to watch as a person with stereoblindness due to strabismus - i don't have the ability to see anything in 3 dimensions because that involves stereovision and I can't converge my eyes, but i can see all the other depth cues so i can get a (somewhat impaired) sense of depth. because of this, i can't at all see the images floating above or below the surface as you say because they rely on stereovision, but the complex ones still have depth to me because of the other depth cues it forces, like motion parallax. it's really cool to be able to appreciate a stereogram because of its other features, even if im not getting the full experience

[@0ADVISOR0]

The holograms look so amazing when you go crosseyed! I love those images where you can go into 'deeper' shapes by just somehow controlling your eyes to do so.

[@scififan698]

Actually with regular stereograms, the trick is to diverge, not converge, but not everyone can diverge at will easily. The thing is: for convergence, the stereogram needs to be built with reversed depth, otherwise it's depth-axis inside-out.

[@mikeuk1927]

@@scififan698 there are parallel view stereograms and cross eyed stereograms. In parallel the left image is on the left and right on the right. In cross eyed on the other hand, the left image is on the right and right on the left. If you look at the wrong the depth is inverted. Just wanted to expand a little on what you wrote.

[@scififan698]

@@mikeuk1927 yes, and for these 'parallel view' stereograms, I found that a lot of people can't pull it off, because diverging the eyes (looking far away, as opposed to the easier cross-eyed) seems to be harder to explain or execute. It is the more natural way though, because it corresponds to what we do when looking far away.

[@0ADVISOR0]

Yes that's what I'm taking about, can you tell me where I could find those images?

[@SteveMould]

@cheesecake there's some good parallel view stuff here www.reddit.com/r/ParallelView

[@Tesseract_King]

I used to do these on CD trays EDIT: I actually learned them from Bill Beatty's website when I was a kid, so it was cool to see him get a shoutout

[@MaryAnnNytowl]

I have to have one of those stereo-vision-3-D pictures a pretty exact distance from my face, and it still gives me a headache 80% of the time. Still, this is a pretty cool video, Steve - thanks! Here's a well-deserved like and comment for the care and feeding of the Almighty Algorithm. ❤️❤️

[@richardpike8748]

Yeah it feels a couple feet away is best for me. Though depending on the pattern / backdrop environment it can also happen outside that range for me

[@ericjx]

As someone that lacks depth perception and can't join the images together.. I am envious of the fully sighted folks who can enjoy this far better than I'll ever understand.

[@dj1NM3]

I did guess that 08:45 that it was created automatically, by machine, because I could just imagine that if it was done by hand, the sheer number of "rage quitted" mistakes would really pile up.

[@nemesisurvivorleon]

Such inspiring channels... all these math / science channels that show how things are made, what can be made, how it works, and the mathematics / patterns behind it all. Seems like infinite potential is right at our fingertips with such simple tools and materials.

[@amarnathparasar5903]

It's a privelage to learn science from Harry Potter himself !

[@UnrelatedAntonym]

Remarkably simple technique. Nice. Love the explainations about the process and what is happening to create the illusion.

[@thewiseturtle]

Pro Tip for seeing the 3D stereogram images: make the video small, either by viewing on a small monitor (like a phone) or by making the browser window smaller, and get quite close to the images, so your eyes don't have to go super crazy crosseyed, and can more comfortably focus separately on the images.

[@merren2306]

for crosseye stereogram its actually easier if the monitor is far away from your eyes. Getting up close to the monitor helps for parallel stereograms

[@thewiseturtle]

@@merren2306 Not for me. Though Steve suggested that these are not crosseyed ones, so maybe that's the difference? Basically, I think that a lot of us are used to using 3D VR headsets where our eyes are right next to tiny images, so it's easier for our muscle memory to figure out how to focus. But maybe I'm weird. :-)

[@merren2306]

@@thewiseturtle the apparent focal point of a VR headset is actually infinitely far away

[@Alexander_Sannikov]

this is crazy. i'm gonna program it and see what it looks like if I calculate perfectly shaped curves matching perspective projection. simulating it has to be much simpler than making physical scratches.

[@wbeaty]

The ideal shape is not a single curve,. Instead it appears as a horizontal band of short segments, like the side-view of a fresnel lens. (For a distant illuminator, the curve should be a parabola, but that only eliminates the spherical aberration and not the vertical "droop" seen at large angles.) The ideal curve should be a broad parabola which has been shattered and then squished into a very narrow horizontal band. (That's what we'd see in a Rainbow hologram of a single glowing point, if we look at it under a microscope.)

[@Alexander_Sannikov]

@@wbeaty i wrote a program that calculates the actual microsurface shape. i calculate normals of individual facets scattered around the surface, rather than curves. you can find the video on my channel. unfortunately the latest video still contains a bug that I fixed, but never bothered uploading another episode.

[@wbeaty]

@@Alexander_Sannikov Heh, now just need some sort of DLP display ...made on one of those twelve-inch silicon wafers they use for making large processors.

[@Alexander_Sannikov]

@@wbeaty i was actually thinking of dlp arrays too

[@richardh8082]

Pair of compasses

[@charlesmayberry2825]

The complex answer to why that point of light works is the Fresnel effect is a thing. The higher the angle of incidence of the light reflection to the viewer the more reflective and bright a surface appears (at the expense of focal light in the case of lamps) Old Railroad lights and the original Fresnel light for lighthouses exploit the shape of the lens with arcs to make them brighter even if it makes them fuzzier, but that's the same effect that is happening here. The example with the sauce pan lid is referred to as anisotropy. These phenomena are both really cool and could be their own videos.

[@DaveTexas]

I’m having trouble focusing on the holograms. I’m fixated on Steve’s lovely beard. A full beard looks so good on him!

[@Tomatsonya]

Immediately won my favor by situating the stereograms for cross-eye instead of diverging

[@bermchasin]

Do you have a CNC? Could try making this with a computer? edit: ah. just got to 8:20. very nice! Do you have a CNC?

[@trailerwookie]

This is why car detailers call all the micro-scratches on vehicles holograms. It is especially noticeable on dark, shiny paint.

[@94D33M]

RIP to those who cannot view crosseyed stuff

[@saturnday160]

Im so glad to finally have an answer for how holograms are made. This makes a lot of sense.

[@ballenf]

Would be cool to coat the acrylic with carbon soot beforehand.

[@xaytana]

There's some parallels to be had with parallax, though inversely. Rather than focusing on a stationary (by reference) object and being the moving (by reference) object, these holograms flip it to where the viewer is stationary (by reference) and the object moves (by reference) with a secondary parallax of the light source that is also stationary (by reference), which is what causes the double-inverse-parallaxing glint; multiply this by what can easily be hundreds of etch lines and glints, and you get a holographic object. Now using parallax as an example is interesting because the best example of it is looking at a distant object at highway speeds, yet highways are typically (or at least optimally) straight roads so you're never actually generating an arc-based parallax, and you deviate further from this arc as the road curves away from the object, and understanding this is where double-inverse-parallaxing of the glint has its best analogous example. I wouldn't be surprised if 3D model to generative etch code does exactly this, parallaxing a point between a light and a viewing source, both of which already conveniently exist within most modelling software, throw in some intended movements and the code basically writes itself.

[@rodrigoalvarez1712]

What are the dimensions of the etched grooves? I’m asking to see if I can 3D print them (with 4K resin printers)

[@walterriblethegreat]

You can actually see the effect with any size groove (or mound/tube)! The layer lines may be an issue for 3D printing, but it should theoretically work. When I first learned about this technique years ago I considered making a large sculpture with polished wire to create a hologram, but the wires in front block the glint from the wires in the back. So you have either have consistency(very few wires) or resolution (lots of wires), but not both.

[@deebznutz100]

When I was a kid I was walking down the street at night and I walked under a tree that had a street lamp directly behind it. The tree had dense but thin branches. As I walked under the tree I kept my eyes fixated the lamp. The light would reflect off of the edges of the branches in a circular pattern. And no matter where I moved, so long as I kept the tree between me and the lamp, the pattern would remain. It almost looked like a light in the middle of a spider web. I feel like these images work on that same principle.

[@douglasjackson295]

I’m good at divergent view stereograms but cross eyed ones are always a fairly fiddly for me.

[@horizon2896]

Looking at the examples at the beginning while going cross-eyed was so trippy

[@josephstarr8342]

i'm so jealous of people who can see stereograms.

[@JoriDiculous]

I can, usually without any effort, but i was struggling with the ones in this video for some reason. Probably because i haver looked at moving stereograms before. How i trained too: everyone say you should look at them cross eyed, i dont (well i dont start off being x-eyed) i try to look straight through them and focus "behind" the images, then they start too merge (when the eyes start going x-eyed without thinking about it).

[@markkalsbeek5883]

It helps me to make the window very small at first, and when I get back into it I can make it larger and larger. That way you don't need to move your eye that far to start.

[@KallePihlajasaari]

@@markkalsbeek5883 You make a important point. With cross eyed most people can handle large convergence angles. With divergent look very few people can diverge beyond infinity focus where the eyes look straight ahead. This means with divergent stereograms it is very difficult to achieve alignment if the images are wider than your eye spacing (60-75mm), with cross-eyed look one can train to handle large images, I can easily make two 20" (diagonal) monitors at arms reach come together by squinting.

[@PeterBrodersen]

It is great to hear @wbeaty being mentioned - the OG KZbin science communicator.

[@DetroitMicroSound]

My sister bought the Styx Paradise Theater LP when it came out. 👍👍 The entire package is a beautiful piece of art. The front of the cover, and reverse, speaks so much! Then the record itself! All laser etched. In 1980, laser etching was cutting edge!

[@sanderd17]

If you have the code to calculate the curves, it should be pretty doable to transform a 3D printer into an etcher. Just adding a spring loaded etcher instead of the print head would do.

[@initials_eve]

Thousands of people sat cross-eyed looking at their screen because of this video and I now imagine them all in the same room..

[@riffraffselbow]

instead of adjusting the length measured by your dividers, you should be able to place the pivot on a 3d surface and use a constant divider width and get at least some 3d effect; at the limit, consider a 10cm high surface with a 10cm divider width; your radius (effective divider width) would be zero, giving you the effect of being "at the surface". This has drawbacks (you can't get as close to the surface as with varying the divider depth) but simplicity advantages!

[@theoriginaltubeofyous]

fun fact about borromean rings is you can have any number you want! 3 is the standard because it is the minimum required and also featured on the family crest of Italian house Borromeo, presumably where they got their name. the discordian mandala is an example of 5 borromean rings and one of my favorite "shapes" or I guess shape groups as it reminds me of non-periodic tilings of 3-dimensional space, fivefold symmetry, Roger Penrose, and quasicrystals. y'know, just fun maths stuff.

[@thegrate1521]

the fact you included the cross rye bits is so cool I think that technique should be more well known

[@giantisopod]

Wow, finally! wbeaty. That's the guy! Been trying to find this channel again for over a decade, couldn't remember what it was called. I thought it had been deleted or I had hallucinated its existence. Now my soul can finally rest.

[@DavidMcCoul]

Those crossviews were cool and I could see them in 3D! All those years of Magic Eye books finally paid off...

[@thedofflin]

The square covering the S blows my mind even though the mechanic to do that is so simple