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Dust and dirt removal after scanning 8mm film


Guy Burns

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Background

I'm on a search for software that has the ability to run through a scanned film and remove a certain amount of dust. Or, a service provider that has such software, and I send them a hard drive and away they go. I don't want the films to look like a restored Blu-ray; I do want some imperfections to remain to give the feeling of age.

 

The films are 8mm, and they will be scanned into ProRes 4444. Dust removal would be best done by Digital ICE during scanning, but very few scanning companies – or machines for that matter – have the ability to detect dust via an infra-red pass and then clone it away. My Nikon Coolscan has ICE. To me it's the most magical thing – the combination of hardware and software accurately removing thousands of dust spots on an old slide. No other bit of computer technology so impresses me.

 

What's interesting to me is that for a static image such as a slide, the only automatic way to accurately remove dust is via ICE. It can't be done accurately by software – yet. That's not so for a moving image, because you have other frames as a comparison. If dust and dirt come and go, they can be detected and removed. That leads me to…

 

 

A Sydney Solution

I spoke with a scanning company in Sydney about this. They said they use their own software which is based on a 5-frame comparison. As I understand it, given a particular frame to clean, the images in the surrounding four frames are compared, and anything that is not on all of them, is cloned away. Something like that. Sounds a good solution. I just stepped through several frames of a very dirty scan, imagined myself to be a dumb bit of software looking for small things flicking in and out, and I reckon I would have done a good job of cleaning. Enough, at least, for my purposes.

 

 

Software I don't want, do want

I don't want software that does everything. This is not a Hollywood restoration project. I just want an elegant piece of software in which you open the movie and can see the frames, you alter certain settings (probably just two or three), press CLEAN and it comes back with a cleaned-up movie. If you don't like the result (too aggressive, too gentle), you cancel and run it again. It doesn't attempt to remove scratches, just small blobs.

 

 

Ques 1

What software is available as a standalone package, preferably on OSX, that uses something similar to the Sydney Solution? It could be part of a larger suite, or an extracted feature sold separately.

 

 

Ques 2

What companies offer a simple, effective, dust-removal service? I don't want grain reduction, colour correction, flicker removal, and so on. Just the removal of smallish blobs that come and go, frame-to-frame.

 

Any comments/suggestions most appreciated.

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There is no inexpensive automatic dirt and dust system for motion picture, and also no Digital Ice like IR system on any of the high resolution scanners for Super-8mm.

 

DCS has IR LEDs in all of their lamp houses and it is theoretically possible to run the DCS Xena Dynamic Perf machine in intermittent mode with IR but it is not enabled yet.

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As Rob said, there is no inexpensive automatic dirt removal software out there that doesn't leave more artifacts than it cleans.

 

The quickest/easiest way to do dirt removal is also the least desirable in terms of quality: degrain the film, run an aggressive noise reduction pass, then regrain the film. This softens the image, removes a lot of texture, and replaces it with artifical grain (that never really looks quite right). We don't do this.

 

The best way to do it is manually. There are tools for this, some are even reasonably priced: if you have Resolve you can do manual dust busting to get the big stuff. Your source files have to be DPX for this to work (it doesn't work with Quicktime files), but it does work. And it's free, assuming you have hardware that's powerful enough to run Resolve -- lots of GPU power is required. Manual cleanup is slow, painstaking work, and costs a fortune as a result. On a typical feature film, it takes one person about 3-4 weeks doing nothing but dust busting to clean the whole film. We've done dozens of feature film restorations this way and it's a slow process. But it's the most accurate, because you instantly see if you're making it worse, and can fix it.

 

When you automate that, you're bound to miss stuff. Even on the very high end, automatic tools have to be used with great care, because they will usually add a lot of their own artifacts. PFClean's automatic tools are pretty good, but the application is a buggy minefield of crashes when you start doing a lot of auto-dirt stuff. Also, it's $6100, so not exactly cheap (though cheaper than many others out there).

 

DigitalVision Phoenix Touch is similarly priced to PFClean, but requires a PC that costs almost as much, so you're into it for over $10k easily. It's got some really nice automatic cleanup tools, as well as a manual toolset.

 

but very few scanning companies – or machines for that matter – have the ability to detect dust via an infra-red pass and then clone it away

 

 

IR dustmaps and IR-based cleanup is interesting, but doesn't deal with a lot of situations you'll hit in restoring a film. The defect has to be a physical thing on the film itself in order for the IR scan to pick it up. If the thing you want to remove is a chemical stain, or a hair in the camera gate, or if the film is a duplicate and contains baked-in dust, it does nothing. I don't think it does much for scratches either since it's only able to pick up stuff on the film that's not supposed to be there. A scratch would, by definition, be the opposite: a lack of stuff (emulsion or base) because it's been scraped off.

 

Unless things have changed, by the way, part of the reason this only exists in a very small number of scanners is that there are (or at least were) exorbitant licensing fees due to Kodak, which holds (or maybe held, not sure) the patent on this technology. I remember getting a quote on a scanner 7 or 8 years ago, and Digital Ice (which just created a dust map to feed into restoration software, where the actual cleanup happened), was an additional $60,000 on top of the cost of the scanner.

 

-perry

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We only use PFClean's automatic mode on shots that have almost no motion, on everything else manual dustbusting is done; if you are very good, you can do about 10 minutes in a day if the film is not too dirty. So, even just counting labor, we are talking about several hundreds per day.

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DaVinci Resolve has a pretty good manual tool for dirt and dust, you need DPX frames for it to work and it's not in any way automatic but it's free.

 

 

I think Kodak has moved on from hammering people over using IR in motion picture tech.

 

Also Filmlight had IR for a long time and there was a court case and everything.

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Thanks for the suggestions. I was pretty keen to try Resolve. Assumed it would have a reasonable dust-busting tool, being part of such flash software.

 

So I downloaded Resolve, installed El Capitan on an external drive to run it, dragged a very dirty 8mm movie into the timeline, and started drawing some rectangles.

 

Is DaVinci kidding?

 

 

Problem 1

There's no sensible undo. First time I've come across an Edit > Undo in any software that doesn't work. Doesn't do anything. Wait… what's this Edit > Resolve Undo right down the bottom? Aha! Yes, that works – but it undoes every clean you've made. You could have done 100 cleans and want to undo just the last one because it looks a bit sus, but no, the whole lot are undone.

 

So, you have two options for Undo: none or the lot. Ridiculous. But maybe I missed something.

 

 

Problem 2

No accurate control about how the cloning is done. You either click on a point – and it clones who-knows-how; or you draw a box – and it clones who-knows how. Sometimes it's okay, sometimes it's not. But if the latter, there's no sensible undo.

 

Now you're listening to a cloning-expert here. I've cloned away hundreds of thousands of imperfections on my scanned slides, using either the Healing Brush Tool or the Clone Stamp Tool in Photoshop. Each has it's advantages in specific cases. But unlike Resolve, PS allows the user to clone very accurately, by adjusting the relative position, size, and blending mode of the tool, as well as zooming and moving the canvas, if required.

 

But with Resolve you just hope for the best. And you can't undo!

 

 

Problem 3

To use Resolve to dust-bust, you have to turn the clip into an image sequence. Well, if I'm going to do that, and if I'm going to clean manually by drawing rectangles, I may as well use PS which offers full control over cloning – and it offers Undos.

 

 

Conclusion

I'm surprised that such a professional-looking piece of software as Resolve offers such a mickey mouse feature.

 

Two good things have come out of this:

  1. I can cross Resolve off the list.
  2. I can put Photoshop back on the list.

 

Adobe and Film Cleaning

Photoshop has the ability to stitch images together. To me, that's pretty amazing image-analyzing technology. If it can determine that the edges of two images are similar, and work out how to join them, it must be able to determine which parts of two images (two adjacent frames, say) are dissimilar. Then it could use it's cloning features to remove that dissimilarity.

 

It seems to me that the technology already available in Photoshop and After Effects would enable Adobe to come up with a viable, virtually automatic cleaning system for film, much like Digital ICE. Under manual override/undo, of course.

 

Maybe it'll come.

Edited by Guy Burns
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Resolve is not a dust busting tool. It's an add-on feature in free software, so I think you're probably expecting too much here. But the algorithms used by the dustbust tool are ported over from the now defunct Davinci Revival, which was quite good high end restoration software.

 

One could use Photoshop for this, but it's not a good idea. A fix that might look completely seamless in a single image can look terrible in motion. Really bad footage can lead to an effect known as "boiling" where a given frame looks fine on its own, but when in motion it looks like the frame is bubbling with fix artifacts that you wouldn't normally see in a single frame.

 

You just can't compare still image restoration tools to motion picture restoration tools because motion picture footage has to take into account the context of the surrounding frames.

 

I've never really used Resolve for restoration beyond quickly looking at what it can do, but I believe you can change the algorithms it uses for a given fix. When I last looked at it there was a preference panel where you could specify the type of fix to use (for example, spatial or temporal, or a combination of both, stuff like that.

 

There's a good reason why restoration software is as expensive as it is - it's highly specialized and not something you can do seamlessly in Photoshop without a ton of work. And even high end motion picture restoration software makes mistakes when automating fixes. We've been at this for 11 years, and it wasn't until this past year that we finally started using some automated software (PFClean and soon DigitalVision Phoenix). It's a *really* difficult technical feat to pull off and it requires serious horsepower to do.

 

It might be possible to do something like this in Photoshop or even command line tools like ImageMagick or GraphicsMagick, but it would be painfully slow and probably not too reliable. And it certainly won't have features like Undo if you're scripting it (unless you're an programmer and are writing your own software).

 

-perry

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A wet gate isn't going to do much. It might get loose surface dust (so will PTR Rollers, which are standard on most scanners anyway), but it won't take off the deeply embedded dirt that's accumulated over the years. a good ultrasonic cleaning could do it, but 8mm Ultrasonic cleaners are few and far between. We're modifying our alcohol-based film cleaner to support 8mm film, but it'll be a few months before that's up and running since we have a million other projects to deal with.

 

For now, the best bet is a gentle hand cleaning using something like Solvon or a similar film cleaning solvent. But that has to be done very carefully or it could cause more damage.

 

The thing a wet gate is really good for is concealing base scratches, and even then, only when the light source in the scanner is collimated light, not when it's diffuse light like what you get in most modern film scanners. Neither will do anything for emulsion scratches, just base-side scratches.

 

-perry

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  • 4 weeks later...

Good suggestion, Freddy, but I'm on a Mac. Anyway, those things without a GUI frighten me.

 

I should add to the list of problems I found with Resolve, after I revisited it.

 

Problem 4

Cloning with the rectangle usually results in a fine outline of the rectangle remaining behind when the clone is finished. There does not appear to be any feathering to disguise the edge of the area that was cloned. Zoom to 300%, do a few clones, and you'll see the outlines.

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Good suggestion, Freddy, but I'm on a Mac. Anyway, those things without a GUI frighten me.

 

 

But there is a GUI for Avisynth: AvsPmod.

I'm using it all the time.

 

Unfortunately Avisynth can not be used on a Mac.

 

Fred.

Edited by Freddy Van de Putte
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One could use Photoshop for this, but it's not a good idea. A fix that might look completely seamless in a single image can look terrible in motion. Really bad footage can lead to an effect known as "boiling" where a given frame looks fine on its own, but when in motion it looks like the frame is bubbling with fix artifacts that you wouldn't normally see in a single frame.

 

I've used Photoshop for cleaning up dust on individual frames but it is a laborious process and you're absolutely right about fixing artifacts occurring over multiple frames looking strange when played back.

I'm surprised that such a professional-looking piece of software as Resolve offers such a mickey mouse feature.

 

 

Resolve is incredibly powerful even in it's free form, a tool worth getting to know intimately if you're into film. Fred's avi-synth tool is absolutely worth a close look, the results speak for themselves. Even if you have to buy a PC to make it work.

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