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Building your own film scanner


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#1 Carl Nenzen Loven

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Posted 09 November 2015 - 12:50 PM

Hi everyone,

 
I am film student in San Francisco. We still shoot a lot of motion picture on film. Problem is digitizing it. Out school has very limited tech to do this. There is outside labs of course, but cost a lot per foot (for my wallet at least :(  )
 
Therefore I was considering building my own film scanner out of Plustek 8200, modifying a plastic holder.
 
So the idea is to have the old style editing reels, with one side motorized moving one frame at the time. And scanning each shot in a lower resolution TIF/RAW file that can be combined later (I expect any short taking up around 300-400 gigabytes). The problem I am having right now is scanning through a timed system.
 
My first idea was to do this manually, but since it is 24 frames per second, and every shot will take minimum of 12-15 seconds it would add a lot of time for me to do this...
 
Anyone that has done something similar. Would be glad for any help.
 
Best regards
Carl

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#2 dan kessler

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Posted 09 November 2015 - 05:36 PM

A lot of people have undertaken the challenge of building their own film scanner.  Some have posted here before.

Among the basic requirements are repeatable film registration, consistent illumination, and the transport system you already have been thinking about.  Not to mention the computer and software that drives it all.

Suffice it to say that building (or modifying) a film scanner is a major engineering project, which is doable, but only if you have the knowledge, skills and tools to do it.  

Not saying you shouldn't try, but the impression I get from your post is that first you are going to have to spend a huge amount of time and money acquiring the latter before you end up with something that scans any of the former.  
 


Edited by dan kessler, 09 November 2015 - 05:39 PM.

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#3 Phil Rhodes

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Posted 09 November 2015 - 06:47 PM

A lot of people do it with some sort of digital stills camera because it's often faster. Modifying an existing slide or film scanner seems like a good approach at first, but the DSLR approach might involve less engineering. You can make most DSLRs take a snapshot simply by connecting two pins together on the shutter release connector, so it's reasonably easy to integrate with whatever's doing the film movement.

 

Repeatable registration is, of course, something that can be fixed in software, especially if you shoot a wide enough frame to see the sprocket holes and track them. You need to get enough resolution that the results aren't unacceptably soft after you've cropped and stabilised.

 

Some commercial telecines use digital stabilisation in at least one axis.

 

P


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#4 Perry Paolantonio

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Posted 09 November 2015 - 08:08 PM

It can be done, but as others have said, it's a ton of effort (much more than you may think) and time, and the results probably won't be as good as what you get with a purpose-built scanner. 

 

Even on a budget, 2k and higher resolution scanning has become very affordable, so it's worth asking around  for pricing. If you're a student, most facilities will also offer student discounts. We do tons of work on student films for people all over the country, many on very tight budgets...

 

-perry


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#5 Robert Houllahan

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Posted 10 November 2015 - 12:10 AM

The only "Commercial Telecine" I know of that had perf based stabilization was the Sony Vialta which had capacitive perf sensors and a opto-mechanical stabilization system. It also used primary RGB LED illumination and a 3-CCD camera.


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#6 Phil Rhodes

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Posted 10 November 2015 - 01:05 AM

My understanding is that Spirit (okay, call it a datacine if you like) uses digital stabilisation in the vertical, or at least film-lengthwise, axis.

P
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#7 Carl Nenzen Loven

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Posted 10 November 2015 - 01:31 AM

It can be done, but as others have said, it's a ton of effort (much more than you may think) and time, and the results probably won't be as good as what you get with a purpose-built scanner. 
 
Even on a budget, 2k and higher resolution scanning has become very affordable, so it's worth asking around  for pricing. If you're a student, most facilities will also offer student discounts. We do tons of work on student films for people all over the country, many on very tight budgets...
 
-perry


Pardon my ignorance but I am having a hard time seeing the issue. I mean each frame would take up to 15-20 seconds to scan but still it would work like a linear editing system, placing the scanner in the middle. It is the automation I feel is the issue, cranking one frame forward and locking exposure I can do already.

And the ballpark figure (except coding the automation) would be around 100 dollars.

Now cheapest I have found for scan is 500 for 10 minutes, that didn't include converting it to the right format...
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#8 Satsuki Murashige

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Posted 10 November 2015 - 01:31 AM

Which school do you attend? Might be worth petitioning the film department chair to have the school invest in a Blackmagic Film Scanner: https://www.blackmag...products/cintel

Of course, if they do go for it you probably will have graduated by then...

Other thoughts, there was a pretty decent commercially available low budget telecine made from retrofitted 16mm projectors made by a small company called Moviestuff, looks like they are still around: http://www.moviestuf...stuff_home.html.

You could send your film there, or crowd fund for your school to get one, or just get inspired by the design and try to make something similar. For instance, you could take a projector with a single frame mode, replace the bulb with a cool low power LED source, and rephotograph the projected still frames with a DSLR. Of course, you'll burn out the shutter of the DSLR after a few weeks...

At least you have access to decent digital cameras these days. When I was in your position a decade ago, I did my own film chain transfers by shooting the projected film image on standard def digital video at 1/30 sec through a piece of Tough Spun gel! Believe it or not, it was still much better quality than the school's telecine. :)
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#9 Pavan Deep

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Posted 10 November 2015 - 03:31 AM

Building a decent scanner is difficult, time consuming and expensive, but it's entirely possible, there are many threads here and elsewhere on the net where people have built frame by frame scanners for transferring Super 8 and 16mm film, look at them. I have built a scanner and it's taken me five years to get it to work the way I want, getting perfect registration and stability, accurately and automatically triggering, getting good macro lens, consistent and even light are just some of the issues.

 

Pav


Edited by Pavan Deep, 10 November 2015 - 03:32 AM.

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#10 Phil Rhodes

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Posted 10 November 2015 - 03:35 AM

I think it's kind of a fun project. Considerable sophistication is necessary for really good results, but it's easier than it's ever been. For instance, doing really consistent exposures with LED backlights requires temperature sensors on the LED device, as temperature variations can alter their output enough to cause noticeable flickering or pulsating problems in the finished footage. But these are all fairly well-trodden paths and there's a lot of information online. The advent of extremely easy-to-use microcontrollers has made it easier still.

 

Still not easy, but entirely doable. I've often considered it as a project I'd like to do for fun if I had infinite free time. I still wouldn't use a slide scanner. The principal problem is registration.

 

P


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#11 Perry Paolantonio

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Posted 10 November 2015 - 08:22 AM

And the ballpark figure (except coding the automation) would be around 100 dollars.

 

 

Honestly, it'd be fun to build, and if you have time, I would encourage you to do it. But it's not as simple as you think. Trust me, I've been working on a rebuilt 35mm scanner for well over 2 years now. It's on hold at the moment because we're too busy, but things that seem like they should be simple often wind up dragging out for a long time while you figure out what's not working correctly and get it fixed. 

 

It's definitely a fun rabbit hole to go down, but don't expect it to be as quick or cheap as you think it will be. I'm fairly certain that anyone else who has done this would agree with me. 

 

Now cheapest I have found for scan is 500 for 10 minutes, that didn't include converting it to the right format...

 
That's expensive. What gauge are you talking about, and what resolution? PM me and I can give you a quote for scanning 8-35mm at up to 6k.
 
-perry

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#12 Sam Javor

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Posted 11 November 2015 - 07:28 AM

I  built a homebrew scanning system for 35mm out of a Dukane 500 filmstrip projector.  I had to saw the tube for the lens mount off if it so I could then get my DSLR close enough to take macro photos of each frame.   The Dukane 500 has a single frame advance controller and I got a cheap shutter release for my DSLR.  Any projector with a single frame advance should work.

I do recall on the Dukane the film is held flat with glass plates that were very low quality so I did remove those... I think with a hammer and punch...but I dont remember...

pictures: 
https://www.facebook...51&l=6600933cf5

and

https://www.facebook...51&l=95f8456524

Here is the 48 hour film project I did using this system and developing (the very expired film) in caffenol.


I actually modified my Arri2B to be hand cranked which was also fairly easy with a modifed film rewind crank and some plastic gears....


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#13 Carl Nenzen Loven

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Posted 12 November 2015 - 09:44 AM

So I will keep everyone more updated, but I have found a friend good with programming and robotics to help me. As well as someone that has a 3d printer and workshop to build the tools.

Of course this is not what average Joe got access to so I am lucky. But I'll try to keep everyone in the loop.

Biggest issue our robotics expert have said is the exact feeding of each frame, so it doesn't overshoot the scanner.
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#14 Perry Paolantonio

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Posted 12 November 2015 - 10:16 AM

You need a method for counting frames based on perforations. You can't rely on steps of your stepper motor because there's no feedback from the motor that a step was successful. That is, your controller could say "go forward one step" and the motor might not, for a variety of reasons. So relying on a count of steps isn't going to work.

 

Instead, you need a through-beam style photosensor to count perfs. Basically the film is threaded through this device, which acts as an optical switch. When there's nothing blocking the beam it's on (or off, depending on the switch), and when there's film blocking the light, it's the opposite state. Your microcontroller tests this to see where it is and your code keeps a running count of perfs. The trick is, you probably need to use more than one, because the switch may change state before the frame is exactly where you want it. With two of these, you can dial in the exact location of the frame (well, not exact, but pretty damned close). 

 

They look something like this (not necessarily recommending this one, but it's similar to what's in our rebuilt Imagica scanner) http://www.mouser.co...tZsZV/noou8/FI= 

 

An alternative is to put a rotary encoder on your stepper motor, and count how many rotations the motor actually makes. It's kind of the same idea as above, only you're testing the drive shaft of the motor, not the film itself. In the Imagica we use both, to cross check that the film is in the right spot, before engaging the registration pins (so the film isn't damaged). The resolution of the rotary encoder is important here, if you're using a big motor that isn't going to make a complete rotation when moving the film. 

 

 

You can rig something like this up yourself using a disc with notches on it and some light sensing diodes. You'd probably want the number of notches on the disc to match the number of steps the motor can do, and that might no be possible to 3D print. I'd opt for buying the parts - it'll be more precise, reliable and will eliminate a lot of variables when debugging. Unfortunately, they'll probably blow your $100 budget...

 


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#15 aapo lettinen

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Posted 12 November 2015 - 12:25 PM

probably the easiest way for 35mm neg scanning is to modify a 35mm movie camera to a small projector by adding a led light behind a modified pressure plate. if you use suitable camera body and good enough leds you can get very decent results :)  it took couple of hours for me to modify a Konvas 1M to a film scanner this way, I use it for b/w film tests so low cri led light is not an issue... 

I would look for a camera body which has 180° shutter and chrystal sync, also reg pin/pins if possible. 

 

my Konvas scanner project:  http://aapolettinen....vas-camera.html    

 

if you have suitable 4k camera with minimal amount of compression and suitable frame rates and shutter angles compared to your 35mm camera body you can usually do something like this quite easily if the 35mm camera is possible to modify for the led light.  

 

If you have ANY kind of decent camera already available for your scanner I think it would be easies to just obtain a mitchell or similar steady enough pin reg camera movement and build the scanner around that. this way you don't have the challenging sync/registration/speed/etc. issues of the line scan design and can advance very quickly towards a working version :)


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#16 Carl Nenzen Loven

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Posted 12 November 2015 - 12:39 PM

You need a method for counting frames based on perforations. You can't rely on steps of your stepper motor because there's no feedback from the motor that a step was successful. That is, your controller could say "go forward one step" and the motor might not, for a variety of reasons. So relying on a count of steps isn't going to work.

 

Instead, you need a through-beam style photosensor to count perfs. Basically the film is threaded through this device, which acts as an optical switch. When there's nothing blocking the beam it's on (or off, depending on the switch), and when there's film blocking the light, it's the opposite state. Your microcontroller tests this to see where it is and your code keeps a running count of perfs. The trick is, you probably need to use more than one, because the switch may change state before the frame is exactly where you want it. With two of these, you can dial in the exact location of the frame (well, not exact, but pretty damned close). 

 

They look something like this (not necessarily recommending this one, but it's similar to what's in our rebuilt Imagica scanner) http://www.mouser.co...tZsZV/noou8/FI=

 

An alternative is to put a rotary encoder on your stepper motor, and count how many rotations the motor actually makes. It's kind of the same idea as above, only you're testing the drive shaft of the motor, not the film itself. In the Imagica we use both, to cross check that the film is in the right spot, before engaging the registration pins (so the film isn't damaged). The resolution of the rotary encoder is important here, if you're using a big motor that isn't going to make a complete rotation when moving the film. 

 

 

You can rig something like this up yourself using a disc with notches on it and some light sensing diodes. You'd probably want the number of notches on the disc to match the number of steps the motor can do, and that might no be possible to 3D print. I'd opt for buying the parts - it'll be more precise, reliable and will eliminate a lot of variables when debugging. Unfortunately, they'll probably blow your $100 budget...

 

Thanks for this. It is great input and hopefully we can overcome these issues. And thanks for the link.

I'll keep you posted on the progress, and the 100 dollar budget is up for change if we can make it work :)

Hopefully solving some of these issues working with 16mm will leave a possibility to also use it for 35mm, but that is a future problem.

 

probably the easiest way for 35mm neg scanning is to modify a 35mm movie camera to a small projector by adding a led light behind a modified pressure plate. if you use suitable camera body and good enough leds you can get very decent results  :)  it took couple of hours for me to modify a Konvas 1M to a film scanner this way, I use it for b/w film tests so low cri led light is not an issue... 

I would look for a camera body which has 180° shutter and chrystal sync, also reg pin/pins if possible. 

 

my Konvas scanner project:  http://aapolettinen....vas-camera.html    

 

if you have suitable 4k camera with minimal amount of compression and suitable frame rates and shutter angles compared to your 35mm camera body you can usually do something like this quite easily if the 35mm camera is possible to modify for the led light.  

 

If you have ANY kind of decent camera already available for your scanner I think it would be easies to just obtain a mitchell or similar steady enough pin reg camera movement and build the scanner around that. this way you don't have the challenging sync/registration/speed/etc. issues of the line scan design and can advance very quickly towards a working version  :)

 
Well the issue is that I want to scan each frame, not film it. Getting a lower resolution RAW file, even if it ends up being terrabytes of shots, is still the way I want to do this. Doing a repro-photograph-system sync could work as well but I feel then we have the variable of the camera as well.

//C


Edited by Carl Nenzen Loven, 12 November 2015 - 12:44 PM.

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#17 aapo lettinen

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Posted 12 November 2015 - 01:21 PM

It's still photographing whether you do it frame by frame or line by line. The difference is the simplicity of the system and the amount of signal and post processing needed. I'm not familiar with the plustek imager design but I suspect you need quite a lot of cnc machining to get suitable film transport parts made out of scratch which are durable enough for continuous motion and 1/1000th inch accurate.
With frame scan you would not need so many custom made parts and so much programming and effort for the system if you would have the video camera available for the project. A precise used camera movement would blow your budget however so maybe the line scan is the only option for you
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#18 Robert Houllahan

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Posted 12 November 2015 - 09:58 PM

Servo motors with encoders are better than stepper motors.


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#19 Perry Paolantonio

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Posted 13 November 2015 - 08:21 AM

Depends on what you're doing. Certainly for constant motion, and for fast shuttling,  servos are better. Steppers are really slow in most cases. But a good microstepping motor/driver can get you some pretty insane precision. The ones in our Imagica, connected to a microstepping driver and geared appropriately, are able to get the film where I want it almost every time. It's not quick, but for the project being described, steppers seem like they'd be easier to work with.


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#20 Carl Nenzen Loven

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Posted 17 March 2016 - 10:23 AM

I have nothing to post here that I can show yet, but me and my friends are still working on a proper motor mechanism, getting it exact so each scan will be aligned. It seemed more possible than we thought at first, and we ended up choosing a sprocket based system.

C


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