How a film camera superimposes the date onto photos

Teardown of a "date back" or "data back" camera and description of how it works: A micro LCD projector with incandescent light bulb!
/ appliedscience

[@kyezaeta]

Such an innocuous little detail that I wouldn't have known to be this interesting if it wasn't for your curiosity.

[@solotekle2999]

Not to Brag, I new about this on my parents camera. the only thing I couldn’t figure out was how the camera print picture on the film.

[@katt2002]

I really thought it was 7-segment LED but he made a point that making 7-segment LED that tiny in 1990 was a challenge, not some technology you casually put in common $30 devices. this mini projector is the perfect solution for the job, really clever and kudos to the inventor. And not mentioned in the video is I think the bulb draws energy from AA battery source instead of CR2025, correct me if I'm wrong.

[@ThisOldTony]

I really enjoyed that!

[@mib5116]

Tot also watching Applied Science.....awesome!!!!!

[@DynoRC]

This is where only_hands meet

[@Markle2k]

Much more informative than a channel such as "What's Inside?" that just destroys stuff for shits and giggles.

[@therealchayd]

"science" vs science.

[@JoranGroothengel]

I really can't stand that channel

[@brien1254]

Joran Groothengel When he bought a new Tesla just because he needed new tires because they were never rotated was when I really lost hope in that channel.

[@DMarko22]

True

[@CarnivorousPlantsAndGardening]

@@brien1254 just rich people showing off the fact that they money...

[@Techmoan]

That was fascinating. Thanks.

[@roncrotzer9861]

Back in the mid 80's I worked for a company as a machinist that made alphanumeric data backs. A row of micro LEDs were set flush to the backing plate and they fired when you advanced the film. The system worked much like a dot-matrix printer. We used a TRS-80 Pocket Computer to input up to 40 alphanumeric characters of text. We mostly sold our system to police departments and federal agencies. Thanks for the video...

[@martinh.3058]

Just to put a few things correct: The Base Colour is not orange: The orange Mask is formed during development and not present prior to it (and it is not uniformly... rather its density depends on the amount of exposure in the area.) The base is usually transparent or of a neutral grey colour. The reason that the numbers are red/orange is a result of two things 1. The sequence of the colour sensitive layers and filters in the film and 2. Only the red layer is sensitive to red light. From the emulsion side to the base the order of sensitive layers (SL) may look like this( there can be more layers but in general it is this sequence): blue SL -(filter passable for green+red light)-green SL-red SL-Antihalation layer(AHL). So why are they red? As it comes the AHL blocks a good part blue and of the green light of reduces the red part (it depends on the manufacturer and what dyes they use). If exposed through the base the light has to travel through the AHL (prevents light piping through the base) and then the red sensitive layer and then the green sensitive and then the blue filter), since the residual light lacks any blue the result are red orangey numbers. The AHL dyes are washed out during development and are never to be seen in the developed film. Anyway film is extremely complex, it is quite interesting what sort of knowledge is needed to make it...and how sensitive to certain things it is.

[@Muonium1]

In the basement at Kodak Research Labs they used to have a secret (known only to the local fire DP at the time for emergency situations) subcritical nuclear reactor that used highly enriched weapons grade uranium and californium (ie. a neutron multiplier) just to produce a neutron beam so they could neutron activate random test lots of film and examine the trace element and even isotopic composition of the product for consistency. The technique was so insanely exquisitely sensitive they could detect the seasonal change in diet of a certain flock of sheep kept specifically for the purpose of producing a tiny trace additive (from the wool if I remember right?) to one of the film base's secret ingredients. THAT'S how complex film production was.

[@martinh.3058]

10mintwo , didn't know that Kodak checked their film with NAA. Something related to this: in 1925 a Kodak emulsion engineer found that if a cow ate mustard seed, the gelantin produced from it increased the film speed.

[@laureven]

Thanks for this 😊.

[@ruevs]

In addition most C41 negative film was daylight balanced (white balance in today's digital cameras) which is 6500K; on the other hand that tiny incandescent bulb is probably about 2000K - and therefore yellow-oragne-ish.

[@PenZon]

I was thinking that the reason for the amber colouring might well be explained by the fact that the light source is an incandescent bulb: when you turn it on, it doesn't just immediately produce white light, it ramps up through the wavelengths as the wire (relatively) slowly heats up. The same is reversed when the bulb cools down. Thus the combined dose over time, i.e. the exposure has a portion of it in redder hues. I don't know if the warm up/cool down time in the cycle is significant enough to actually make any difference, but this was my first hypothesis.

[@mohdghadiyali]

My dad was a photographer, you just solved one of the mistries of my childhood. Thanks

[@Flumphinator]

>probing a camera that was $30 30 years ago with a $10,000 oscilloscope That's the stuff.

[@ToriKo_]

Mike Donaghy the link isn’t working for my device - how much is it?

[@pluscrafter7117]

up to 22'200€

[@ToriKo_]

Pluscrafter Jesus Christ

[@marios1861]

@@ToriKo_ oscilloscopes are the most important tool for any kind of electrical and electronic engineering

[@justy256]

eBay searches "Tektronix mixed signal oscilloscope"

[@jincyquones]

11:43 🙄 Typical eBay listing... "[UNUSED] USED. TOTAL CONDITION: UNUSED. An item that has been used previously"

[@abyssstrider2547]

And don't forget the text which says: an item may have signs of...

[@abyssstrider2547]

@@squishy3217 Woah is that what it actually says?

[@futureboy7653]

It has a quantum condition.

[@exys2086]

@@abyssstrider2547, haha, it's most probably a joke x)

[@abyssstrider2547]

@@exys2086 I know but its quite true

[@enda320]

I've seen it so many times, never thought about it or how it was done.

[@volvo09]

Yep, and this explains the color and focus fuzz. Awesome!

[@demandred1957]

I was curious about how it was done, but I wasn't about to tear my Minolta camera down to find out.

[@demandred1957]

@@NerdyNEET Are you young? this was all over the place mid 90's-early 2000's

[@mattiloponen92]

Same

[@DetectiveThursday]

NEY Industries it’s helpful for things that need the date and cannot be easily reproduced. For example, police recording evidence and also need to record when that evidence was found

[@SireSquish]

Invariably, Applied Science shows something that would be otherwise mundane to be actually fascinating.

[@mlittletn]

Fascinating breakdown. Never occurred to me how that date got on there. Now seeing the breakdown I’m really impressed with engineering involved to get that date to show.

[@Guysm1l3y]

I love that this was from back in the day when there were still screws to remove. These days it more likely than not would be one ultrasonic welded hunk of plastic that you'd have to destroy to get into.

[@StuSona]

First thing I thought when I saw the assembly.

[@pilotofjet]

I teared down a "new" film camera from the 2000's (kodak aps) to re-use the photoresistor in an older , easier to repair film camera and you are completely right, it was easier than items from today but not as easy as the old camera

[@rkan2]

Products from Japanese brands that are not meant for single use, still usually contain plenty of screws.

[@cybercat1531]

I've taken apart several modern cameras, and anything that wasn't an ultra cheap trash camera is put together with plenty of screws and clips. No fused plastic 'rivets' or much glue at all. Everything from Nikon Coolpix L20, various small Fujis, an HS50, small Canon A480, ,G15, Canon 7D MK 1 and 2, not to mention several no name brand Chinese cameras. All perfectly disassembleable, repairable and reassembled without much fuss. Though it does require patience, a microscope and steady hands. Some soldering also required to disconnect ribbon cables.

[@ArchangelExile]

@@rkan2 This

[@whuzzzup]

4:10 I also always casually measure a voltage with a $15k scope.

[@TickyTack23]

In 70 years the date will be accurate again.

[@ToriKo_]

TickyTack23 fuck 2090 is only 70 years away

[@ArchangelExile]

@@ToriKo_ Don't worry, we'll probably be dead by then.

[@ToriKo_]

ArchangelExile with rising life expectancies, possibility not

[@GRBtutorials]

Tori Ko Also, don’t forget about the younger viewers.

[@smooooth_]

@@ToriKo_ I'll just make sure I eat really really unhealthy

[@1944GPW]

Intriguing teardown, thanks for showing how it works. Regarding mechanical film timestamping the Databack has precedents. During WWII and after, some aircraft photo reconnaisance cameras had timestamping on the film. I have one such camera, it's a british Air Ministry Type F46, 5" focal length lens taking a 2"x7" negative, running on 24 volts. On the bottom face of the camera body casting at the righthand side is a small box housing (labelled 'F46 WATCH UNIT' and A.M. number) that can be removed by sliding off. Inside is some black felt and a circular cutout for a tiny fob watch of no more than 1" diameter. Inside the housing body where the box attaches there are two festoon light bulbs to illuminate the watch face, and a 45 degree mirror and light pipe extended to the corner of the film plane to record the time of day the photograph was taken.

[@aetius31]

Still the sharpness is impressive for a point source that close

[@netpilot5]

Actually, it always used to bug me that the date was so blurry. A tiny plastic lens could possibly have focused the incandescent light better.

[@o0julek0o]

If you think about it, the shadow projection (so how this masks off the areas around the numbers) is only suitable for close projection. The further away the little screen would be the blurrier the numbers should be until they are essentially invisible.

[@rafitheredfox328]

This reminds me to when I found an old photo camera in my grandmother's home, which I took to bits, because my grandmother didn't need it anymore and affordable digital cameras already existed, because it was back in maybe in 2006 or 2007. I also found such a tiny LCD-screen, which I instantly new, that it was for the date "printing" but I don't remember if it was located at the back of the film or in front of it. What I find amazing btw is that analog photo film develloping services still exist here in Germany in some supermarkets considering that digital cameras are now omnipresent these days. You can also find such tiny LCD-screens in projector alarm clocks. I got one for about 1€ on a flea market and took it to bits and found an LCD-screen of a similar size.

[@vinesauceobscurities]

RIP film camera 1990-2019

[@onyourface207]

Vinesauce Obscurities what technology will last nearly nearly 30 years these days.

[@saltysoysauce954]

@@onyourface207 My computer probably, oh and also my camera apart from the batteries in it

[@yootoob6003]

My Nikon FM2 will live forever, it has no date back

[@onyourface207]

SaltySoySauce 30 year old computer hahaha! What OS?

[@StraightOuttaJarhois]

just a little over two months away from retirement :(

[@alexcavalco2815]

If you flip film around and expose it through the back, it shifts everything red too. A few companies like Lomography sell film that was re-rolled the wrong way to get the effect--called redscale. The red dye layer is also the last layer that light hits with color negative film.

[@b6983832]

This is based on the fact all silver halides are sensitive to blue light. If exposed correctly, the blue light would be filtered out after the yellow (blue sensitive) layers, When exposed from the back side, this is not the case.

[@RandyJames22]

This reminds me of the scene in _Alien_ where Ripley is accessing the MU/TH/UR 6000 computer. It shows a projection of the screen on her face, but when I think about it, there's no way that she could read the screen that way.

[@renakunisaki]

Modern films where all screens are transparent for some reason, but when viewed from behind, the image isn't mirrored.

[@TheAechBomb]

@@renakunisaki I like to think they just mirrored the camera image

[@JuiceJive]

2001 has a similar scene in the close-up shot of Dave in the pod. That's a fairly common trope in movies with computer/radar screens and it always bugs me. tvtropes.org/pmwiki/pmwiki.php/Main/Cukoloris

[@webchimp]

@JuiceJive That and having bight lights in the helmet lighting up the person's face.

[@didzisveinbergs571]

Such a cool teardown, thanks! There's another thing about the date always being orange: colour film actually consists of several light sensitive layers, each sensitive to different light. The layer closest to the base of film -- and, therefore, the closest to the date imprinting back -- is sensitive to red light. So, when the light hits the film, it hits the red-sensitive layer first, which makes it this reddish colour. The same effect is sometimes done on purpose: the film is rewound the other way around, with base towards lens and emulsion towards the pressure plate. The resulting pictures are a reddish colour, much like the date on the photos. As a result, this is called "redscale". I suspect that with redscale film, the date would actually be white.

[@TheDoomWizard]

I'm 31 & been a photographer half my life & still never knew this. This video is a gem. Thank you.

[@feltusfeicit]

“Red scale” is a process by which film is flipped and exposed backwards (colour neg), and this gives a red tint to images. This is due to the order in which the colours are layered: longer wavelengths penetrate deeper, so red is always the closest to the base of the film. This is why the numbers have a reddish tint.

[@Luchoedge]

Outstanding! the ingenuity used in some everyday objects really amazes and amuses me to no end! Thanks a lot for your work! I really appreciate it!

[@NoName-ik2du]

I clicked this thinking, "Man, a fourteen-minute video on camera date superimposition? This is going to have a lot of fluff in it," but much to my surprise, this entire video was useful and engaging. Thanks for the interesting teardown.

[@oetken007]

The most interesting things are these small details we have around us all the time but no one questions it's function or design! Thank you!

[@ut4321]

This is wonderful. All the steps to figure out each element were fun to watch. I am glad I watched until the end, because I kept wondering "wait, the date display is BEHIND the film!" Fun video!

[@realpdm]

I honestly never wondered how this was done but I am now glad to know and I wonder why I never wondered because it is pretty fascinating and unexpected . Thanks for sharing!

[@clarkgwillison]

I loved the shadow puppet light source demonstration, illustrated the concept perfectly

[@johnmccanntruth]

I feel like only us old guys can really appreciate this. That time stamp was a revolutionary process in photography. Amazing that we find out 25 years later how it worked...

[@resneptacle]

Nah

[@ilanpenkower]

I was looking at an old picture of my dad I have hung up in my dorm, and I was wondering exactly this. You explained it wonderfully, thank you

[@IanGrams]

Thanks for feeding my curiosity, Ben :] I'd never thought about how that works until now. Really quite interesting to see an LCD and incandescent bulb working together.

[@MrGeoffHilton]

This channel is totally compulsive viewing, great work and hope you never get tired of doing it. .

[@ChristopherWoods]

So awesome. Thanks for doing this and finally satisfying my inner childhood curiosity. Some great creative engineering to a price point to make this happen. No way I could afford to disassemble my film camera when I was young to figure this out!

[@GrayHatter]

Psh, that camera is good for another 2 months at least!

[@sopgenorth]

And then it'll be good for your kids/grandkids again in 2090!

[@weithiamneo1442]

Maybe cost of film and development will cost more than the camera now.

[@PirateRadioPoland]

@@weithiamneo1442 I can't predict much about the cost of film, but development is - and most likely will still be - dirt cheap and you can do it at home. In a pinch, you can even process a C41 (color) negative in ancient (created in 1890s) Rodinal, or even coffee (google: caffenol processing). Of course by doing that you only get black & white pictures, but hey, that's still analog photography, with the added fun of experimenting!

[@among-us-99999]

Jakub Dołęga wouldn’t analog photography imply that it uses analog electronics?

[@PirateRadioPoland]

@@among-us-99999 Analog photography traditionally means using analog medium (photosensitive film) to capture images. The control electronics don't really matter much - a roll of 35mm film would work the same way in 1925 Leica and in 2018 Canon EOS-1V. Now that's some serious backward compatibility!

[@neotoy]

That circuit board trace layout is a true work of art, whoever did the layout for that was a master.

[@ozzy1280]

This is incredible. Would never have thought such complexity lies behind such a tiny result. Makes me think about all the crap around me and all the years of scientific and engineering iteration and progress that led to it. Mind = blown.

[@kjamison5951]

I owned a Ricoh camera with this feature. Given the LCD tech at the time and ‘reverse’ LCD displays, I figured this was the setup but it’s still so cool to see it taken apart.

[@snowdaysrule]

This was very cool! I'd never thought about the mechanism of the date display on a film camera. As a kid one of my favorite things to tinker with were disposable instant film cameras that I had gotten for free from my local drug store. They were this really cool mix of mechanical parts and electrical circuitry, all under the influence of cost-optimization which resulted in a ton of simple, yet genius design choices. Due to being disposable these cameras did not have the date display feature present in this model so I'd honestly never thought about it since the cameras I had on hand to explore did not have the feature.

[@justy256]

I always find your explorations interesting- and informative.. and articulate.

[@antoniomaglione4101]

I have always been curious of how the date camera back worked. Fourty years late, I have found the answer you provided! Thank you very much.

[@ArtturiSalmela]

I was wondering about this just the other day. Using a point-source without optics didn't cross my mind. Very clever indeed!

[@zerocreatividad]

That's great!, thanks for showing this, i still takes pictures in old cameras with film and this was super interesting. The reason for the white light turning out red shifted on the film i think it's because of the composition of the film itself, which has 3 color layers i think being the last one (the closer to the back of the camera) the red one, which is the first layer that hits the LCD projector. There's a whole artistic technique in old photography called Redscale which makes use of this property of the film, the film is put on the camera inversed, so the red layer is the first to receive the light coming through the lens and produces red toned photographs.

[@rselvarajanMBA]

I have seen the dates in old photos but never thought the process would be so fascinating 👍 Wonder how many more fascinating processes I miss everyday.

[@alexecheverria]

I knew the man who patented this: Lester Wolfe.

[@alexecheverria]

web.mit.edu/spectroscopy/events/wolfe.html

[@TheTAEclub]

That is so cool!!!

[@Filaxsan]

Woow :O

[@MaleGeminiCat]

Cool

[@southerncharity7928]

@Christian William boyfriend

[@snacksy7754]

These engineer guy type of videos are great. I know they are time consuming, but allways verry enjoyable!

[@DisdainforPlebs]

Wow this guy actually dremels a hole in his precious camera with which he has some good memories... quite some dedication, thanks man!

[@leafhappy]

Beautifully presented. Really appreciate the weave and mend that went into this film :D

[@billythebake]

Found this channel recently; been 'going down the rabbit hole' w/these vids Just wanted to say: keep up the good work!

[@AndyCallaway]

Ok, that was more interesting than I thought it would be.

[@warrenmacdonald1372]

Thanks for the superb video. I have a Canon A-1 which I purchased in 1979, and it came with the data back, much like the Nikon except the wheels were not interchangeable. The whole data back came off as the back of the camera and the cable ran into the sync port on the camera, so the date would be applied whenever the shutter was tripped. There were three intensity settings based on the ASA of the film you're using. The light emitted was a bright white, and this resulted in at pleasant Orange image on the film. As I recall it used its own Mallory PX -28 6V battery, which is what the camera also used. Past memories, thank you

[@nrdesign1991]

That is indeed super clever. The optical path has some baffles that eliminate reflections from the light path

[@MaheshJoshi]

Amazing technology. I used to have a Konica Minolta camera during 1993-2000 and I have prioritized it over then hot favorite Kodak film cameras because it has date and time stamp feature. Although I paid few buck more, it was a big amount in those days. When I purchased digital cameras I disassembled the Minolta one and kept its back door (containing date/time lcd) and its flash with charging circuit and a big capacitor. All is still in my junk box.

[@FesixGermany]

Watching someone explain how a camera works with a roll of film makes me feel so old...

[@cpufreak101]

Perhaps that could be something I can try to film. Have an old camera from 1957 that's 100% mechanical, and it's a good camera to demonstrate fundamentals on (and in fact, is how I learned the fundamentals as I grew up after the film era lol)

[@CraigHollabaugh]

Nice find, love the optics slant. Thanks.

[@WillProwse]

You have the coolest videos man. Always unique

[@chris24hdez]

Very cool! Never even considered how it got on there! I wish all negatives had a way to encode time stamp to get placed on the back of prints or optionally in cleaner font superimposed on the image like with APS magnetic. It would save me lots of research time when trying to add dates to massive photo collections

[@awgybop1]

Great video, showed exactly what it promised. This is a great example of a video where dislikes do not make any sense; seriously, why would someone dislike this video? It showed exactly what it said it was going to, and even when into detail about the components.

[@plebcrabslayer]

No three-minute introduction, no thirsty valediction, the video is exactly what the title says; oh, and it's interesting! You hit the quadrifecta, sir.

[@VitorMadeira]

OUTSTANDING exceptional super-high-quality content video! I loved this one in particular. Thank you and greetings from Portugal.

[@arthurdent5536]

Great Video! I didn't think, this little detail could be so fascinating. One thing though... *happily touches film with bare fingers* TRIGGERED

[@Mariano.Bernacki]

Content like this is why I'm subscribed!

[@PeterAbt]

Thanks, unexpectedly interesting again! Amazing what interesting Details you analyse out of this stuff all the time!

[@CyrilCavadore]

Those videos are really great, and I love this kind of explorations !

[@vjm3]

The moment you mentioned it projects light on to the film, I said to myself "Wait, how does it use only light to make the numbers on the film?" The second you mentioned how everything needs to be absent of light, or it'll ruin the film, I realized the light it projects through is specifically ruining only that small section of the film to MAKE the numbers! So what we're seeing on a photo is in essence a section equivalently "scratched off" as if you were removing only part of a tint off a tinted window. It's so simple, yet cool. I just assumed this whole time it was digital, even back then.

[@L0j1k]

Ah, hell yeah, man! I was wondering exactly about this a couple months ago and here we are! Couldn't ask for a better means of finding out.

[@MaleGeminiCat]

Your curiosity solves my long time question. Thanks. I love your channel.

[@Zebra_M]

Today on "Things I didn't know I wanted to know until I read your video title..."

[@UpenShenoy]

Loved this vid. So much learning. Creative engineers, can. Imagine the challenges of those days limited by the tech available and cost

[@choninwong355]

I recently brought an old date back camera which is the same type my mum used when I was a kid. Unfortunately, after the New Year Eve it turned to 1980 instead of 2020 and I really want to hack the little piece to extend the limit of date. Camera with date printing back has special meaning to me and I will look forward to your following videos.

[@choninwong355]

There is almost no information about date back camera so this video means so much to film camera photographers.

[@justinoblanco]

Took me a couple of days to realize that I didn’t know how this worked, and that I was interested to find out. Glad I watched. Very curious device.

[@stefankuttenreich8668]

Finally a question i can answer @ 12:45 @appliedscience The date appears red because of the chemical emulsion in the film, there are 3 types of chemical in a film layered up over each other. Normally, when you shoot the film "correctly" the blue sensitive layer is up front, then comes the green one and then the red one. But if you shoot the film flipped, the red sensitive layer is the first one that is exposed to the light, some photographers even shoot photos like this intentionally to give the film a red look, that's also why this style of shooting is called "red scale". And thats exatly what happens here, the photo is still exposed the right way, but the data back exposes the film from the other side hence it appears red/orange.

[@FuzzyTekShow]

It never even crossed my mind to wonder how this was done until I see this video title. Very interesting, thanks for the great video!

[@gloverelaxis]

What a creative & clever system! Great video.

[@Spender604]

Always interesting to see the ingenuity behind cheap solutions. The engineers really have to be creative.

[@BuckJolicoeur]

Very cool, I've wondered about this. Realising that the negative creates the orange colour is a nice realisation from the deconstruction.

[@janezhen9125]

It is so clear that every minor part is explained! Thx a lot!

[@marctronixx]

KZbin recommendations are on point again. I think YT knows me more than I know myself. Never knew this channel existed but Its exactly in line with my interests! Will be looking at other videos on this channel... thx KZbin ..

[@initialb123]

i really appreciate your uploads , thank you for doing what you do.

[@MLGJuggernautgaming]

Once again something I never thought about but find very interesting

[@SVanHutten]

Amazing! There are tiny rectangular cut outs on the PCB along the light path which I guess are meant to avoid internal reflections on the green PCB material by letting the light pass thru and then be absorbed by the black plastic case. Great video on an apparently trivial subject!

[@TheLefse]

Fascinating! Always wondered about those... very cleverly engineered.

[@pomonabill220]

I have always wondered about this. Thanks for the teardown and explanation!

[@simontay4851]

Also part of the reason the date appears red is because the tiny bulb produces a very warm colour temperature. Try replacing the bulb with a blue or very cool white LED and the date might not appear as red in an actual photo. Maybe pink, yellow or warm white, im not sure. Shining an LED torch through the film isn't enough. What ever colour the date would appear doesn't really matter anyway. Everyone uses digital cameras now. There might be some niche applications/reasons a film camera is still used.

[@Nitrxgen]

he literally disproved that at 13:22 with his cool white led torch, watch the video man

[@simontay4851]

Im going to rephrase my comment a bit.

[@samyish]

Fascinating! I was literally just thinking about this yesterday and today this video comes up as a recommendation.

[@adamkendall997]

Well you definitely voided that warranty.

[@DukeBG]

oh no, not the 30 year warranty

[@garethronaldo8692]

@@DukeBG 😂

[@gyroninjamodder]

I doubt there was even a warranty to void.

[@sirzebra]

@@gyroninjamodder i doubt you grasp the concept of humor.

[@hardlyb]

I always learn something from your videos. Thanks.

[@electronicsNmore]

Great video. I remember when I was a 8 -10yrs old, how popular Polaroids were.

[@crobles1973]

Thank you. I always learn something new from you that I never thought I'd like to know.

[@fromjesse]

As a kid I had an LCD calculator and the LCD did not have the front polarizer glued down, so I'd take it apart and flip it over and the LCD would then be all black except white segments. Looks like how they did your little LCD!

[@johanlaurasia]

Always wondered how that worked... neat teardown and explanation

Awesome video!!! Thanks for keep doing those! Best regards from Brazil!

[@mschorer]

Oh boy!!! Thank you for finally lifting this secret! I was wondering myself for ages, how this works! Pretty genius 👍

[@skatiruas]

9:42 If you notice it had other slots for mirrors to go in, with the matching holes in the circuit. Therefore I'm assuming they could be fit for different film sizes by just changing the mirror position and the back plate, that has the lcd fixed after this position. Cool.

[@RamLaska]

VERY nice analysis. I’ve often wondered the same thing.

[@SeanBZA]

Very nice. The long light path to the LCD also adds in the inherent ability to not have a focal plane, as the distance from the LCD to the film will vary slightly due to temperature and the back of the camera moving slightly, yet the superimposed date is always going to be sharp as it is a shadow, and not formed by a lens. Only variation from changing back position is a slight change in image size, and that is a much smaller change compared to having an out of focus image. As to the slower update of the LCD, that probably is also due to the polarising filters and thicker fluid inside, to get a denser image contrast. Plus there is also probably a IR cut film applied to the one side, as the IR from the lamp would bleed through the LCD anyway, due to the long wavelength, so you would need some form of coating to either reduce this, or the front surface mirror is dichroic to not reflect the IR onto the LCD.

[@bendito999]

Is this possibly the cutest lil 7 segment display ever made? I think so.

[@avejst]

Nice design Thanks for the teardown 👍😀

[@sedrickgates1]

Hi, the orange mask is there and for a good reason. It has to do with color contamination. It is there from the start and part of the process to obtain accurate colors for the printing process. The orange/redish colour of the numbers comes from the bulb being a normal 3200k type and film used is daylight (5500k). Also color will vary with film sensitivity from dark red to brighter yellowish tint (50 iso to 3200 iso for exemple) For more info this link, section 3 will provide accurate informations.. www.sebastian-schlueter.com/blog/2015/8/27/understanding-color-negtaive-film-for-scanning