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Film Scratch removal


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#1 Patrick Neary

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Posted 25 February 2009 - 09:21 PM

Ooof.

Does anyone have a recommendation on any good scratch removal techniques available in or for Final Cut?

I had three rolls of 35mm go to telecine last week with corn-rows furrowed into the film, spread nicely across the whole frame and running from head to tail; the entire project (an animated short). They look to me like base scratching, or maybe very shallow emulsion scratches because they tend to disappear in dark areas (and show up in light areas) and they don't really have any color.

(I don't know for sure because the film was sent back to the lab where apparently it's such a high priority that it's been sitting there since monday and no-one has bothered to look at it yet, but that's another story...)

I tried a FC filter from Mattias Sandström, but the scratches weave just enough that it doesn't really work, plus there are so many to deal with that the filter would have to be applied half a dozen times or more to each clip.

At any rate, my gut feeling is that the months of painstaking work are down the flusher, but I'm cutting it anyway hoping I can mitigate at least some of the damage with a plug-in or some kind of filtering. At the worst I can turn it B&W and just call it "old film look" but I'd really rather not.
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#2 Keith Mottram

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Posted 26 February 2009 - 07:30 AM

Ooof.

Does anyone have a recommendation on any good scratch removal techniques available in or for Final Cut?

I had three rolls of 35mm go to telecine last week with corn-rows furrowed into the film, spread nicely across the whole frame and running from head to tail; the entire project (an animated short). They look to me like base scratching, or maybe very shallow emulsion scratches because they tend to disappear in dark areas (and show up in light areas) and they don't really have any color.

(I don't know for sure because the film was sent back to the lab where apparently it's such a high priority that it's been sitting there since monday and no-one has bothered to look at it yet, but that's another story...)

I tried a FC filter from Mattias Sandström, but the scratches weave just enough that it doesn't really work, plus there are so many to deal with that the filter would have to be applied half a dozen times or more to each clip.

At any rate, my gut feeling is that the months of painstaking work are down the flusher, but I'm cutting it anyway hoping I can mitigate at least some of the damage with a plug-in or some kind of filtering. At the worst I can turn it B&W and just call it "old film look" but I'd really rather not.



I'm afraid there is no quick fix for this. To do it properly is a frame by frame job, cloning one clean part of frame to another. Time consuming and if you do it at a post house very expensive.
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#3 Dominic Case

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Posted 26 February 2009 - 06:16 PM

I'm afraid there is no quick fix for this.

Huh?

If they are base scratches or colourless emulsion scratches, then there is nothing wrong with your image. The lab should print a wet gate IP and transfer that.

You don't say how the scratched happened. If it was during lab processing, then the lab ought to do this at their cost. Even if you have to pay for a wetgate IP it would be cheap compared with the time you'd take to try to repair the image digitally.

Moreover, if they are base scratches, then a wetgate would simply make the scratches irrelevant - you will have an unblemished image. If you try to restore the image digitally from a telecine transfer that includes the scratches, then you will be, at best, replacing lost pixels with borrowed ones from nearby. Not the same thing at all.

If you fould a lab with a wetgate telecine, you'd have the job done right away, but I haven't come across one of those for a long time.
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#4 Patrick Neary

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Posted 26 February 2009 - 07:59 PM

Thanks for responding Dominic!

The scratches are numerous and essentially continuous across 3 separate rolls of film. What seems particularly telling is that the scratches are very consistent where the rolls join, so that they just continue from the end of roll 1 to the start of roll 2, etc.

Although one can never be 100% sure, I took great care to scratch test the Mitchell and mags (they're mine) before shooting, as well as with each mag change. There were three separate rolls run through two different mags, and I've never had any kind of problem with the camera before, and certainly nothing this egregious.

When the transfer house noticed the problem I loaded up the camera with the remainder of (unexposed) roll #3 and ran off 20-30 feet and the film was pristine.

That and seeing that the scratches weave a bit during their run makes me think it happened at processing or during the prep for transfer (some prep!), both of which happened at the same facility. I still haven't heard back from them, so I'll wait to see what their assessment is.

If the lab takes responsibility then I may push for an IP and retransfer.

What kills me is that the film made it through the lab and prep with no-one there noticing a rather outrageous problem. Believe me, you wouldn't have to look very hard to notice this mess.
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#5 K Borowski

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Posted 26 February 2009 - 08:06 PM

Thanks for responding Dominic!


Do you have the film? You'll want to make sure the scratches are on the base (glossy) side. Although, from your assessment, it sounds as if this is the case. All but the shallowest emulsion scratches tend to be colored, as they take out actual dye layers from the film.

If the lab doesn't want to take responsibility, showing them pristine film from the same camera and magazines should help sell your case.

Honestly, how is it that this stuff still happens with modern processors and techniques?

Looks like someone was twiddling their thumbs instead of tending the machine.
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#6 Dominic Case

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Posted 26 February 2009 - 09:57 PM

It is really important that you get a visual assessment of where the scratches are, which side of the film, and how deep. Really,it's the easiest thing to do, there is no reason why the transfer house couldn't have looked at the neg before sending it back to the lab - after all, there is a possiblility that they damaged the film on the telecine!

You should persist with the lab (or the transfer house, wherever the neg is right now) and insist on a visual inspection and report immediately. (It sounds as though it's not convenient for you to go in, maybe they are in different cities to you). But it might only be three rolls of neg from a minor client to them: to you it is 100% of a long term animation project that has been wrecked. They should realise that a wetgate IP (if that turns out to be a good solution) is a really really cheap way for them to get rid of this problem: the cost of a reshoot is not something they would want to contemplate (though you can mention it!), but if it turns out to be a lab problem, even covering your stock costs would be an actual cash cost to the lab, whereas the cost of an IP is mostly an internal cost they can absorb.

The only thing that worries me about the diagnosis of this is that you say the scratches are easier to see in light areas. Are they dark or light scratches? Cell (base) scratches would normally be white as they refract light away from that part of the image. Dark scratches do suggest that image dye is removed. That's why the visual assessment of the neg is vital.
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#7 Joe Riggs

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Posted 31 March 2009 - 02:27 AM

I am also interested in any software that can remove or lesson scratches/dust.

I received my footage back and something in the gate (I think) not only obscured part of the frame but also caused a small but noticeable scratch throughout the footage. How do you know if the scratch occurred while filming or at the lab?

thanks
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#8 K Borowski

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Posted 31 March 2009 - 08:11 AM

I am also interested in any software that can remove or lesson scratches/dust.

I received my footage back and something in the gate (I think) not only obscured part of the frame but also caused a small but noticeable scratch throughout the footage. How do you know if the scratch occurred while filming or at the lab?

thanks


Well, it sounds more as if you had hair in the gate. That is totally different than scratching.

Often, you can supposit where and how the scratching occurred if it all comes from one mag, or I seem to remember that processor scratches tend to be weavy and camera scratches tend to be straight, but it isn't always definitive.

It helps to have a scratch test available. I believe negative insurance covers reshoots or repairs, probably whatever costs them the least amount of money, in the case of severe scratching.

You need to read the thread though instead of just skimming it. A wet gate transfer will essentially eliminate the scratch with no digital work necessary.

Scratch removal is painstaking and tedious on a computer.

Off topic, but I just saw an HD transfer of "American Beauty" on TNT the other day, and there was a faintly visible partial scratch running down the right-had side of the frame for the entire film. Kind of hard to believe that such a recent movie would allow what I am assuming is their master positive element to get damaged, and then just to transfer it in that condition anyway. . .
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#9 Richard Boddington

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Posted 31 March 2009 - 06:59 PM

Now did you do your test running at 24fps or single frame?

There is a difference, scratching is much more likely to occur during single frame mode than real time.

When you say: "That and seeing that the scratches weave a bit during their run makes me think it happened at processing or during the prep for transfer"

I would tend to disagree, registration stability goes down in single frame mode on many cameras. So the scratches are weaving because they are being applied to the neg as the single frame comes through the gate in a less than precise manner.

There are only a handful of 35mm cameras out there that will do single frame to perfection, I always had good luck with the Arri III for stop motion work.

R,
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#10 Patrick Neary

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Posted 31 March 2009 - 08:08 PM

Hi-

It's a moot point now because the lab determined that the film jumped a roller during processing, they took care of the problem and I've got a very nice HD transfer (with a kind of electronic "wet gate"), sans scratching.

I'm not sure what cameras you're referring to, but a Mitchell is not going to be more prone to scratching or suddenly develop bad registration because it's running single frame. There's a reason these things were the go-to machines for effects and stop-motion work since the dawn of time.

Just for my own edification I threaded up the Mitchell in the most heinous ways I could think of, with upper and lower loops mashing up inside the camera body, passing on the wrong sides of the mag rollers, you name it, and I could not get the camera to scratch the film.
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#11 Richard Boddington

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Posted 31 March 2009 - 08:17 PM

I'm not sure what cameras you're referring to, but a Mitchell is not going to be more prone to scratching or suddenly develop bad registration because it's running single frame. There's a reason these things were the go-to machines for effects and stop-motion work since the dawn of time.


Mitchells are pretty good which is why they where used for a lot of single frame work.

But, I have seen a number of cameras more prone to scratching and poor registration on single frame vs 24fps.

R,
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#12 Dominic Case

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Posted 02 April 2009 - 12:33 AM

I could not get the camera to scratch the film

. . .. but that doesn't mean that a camera can't or won't ever scratch film - and don't you forget that ;)

Good result for you though, that the lab foound a processing fault and fixed up the problem.
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#13 John Sprung

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Posted 02 April 2009 - 02:18 PM

To do it properly is a frame by frame job, cloning one clean part of frame to another. Time consuming and if you do it at a post house very expensive.


Actually, with the Digital Vision and MTI boxes, this kind of fix is now highly automated, and a relatively quick and easy thing for a post facility. But still not exactly cheap.

http://www.mtifilm.c...rect/index.html

http://www.digitalvi...vnr_asc3_me.htm





-- J.S.
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#14 Joe Riggs

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Posted 10 April 2009 - 08:55 AM

Maybe this visually will help the more experienced figure out what happend?

The scratches, are present throughout the whole roll, the number of scratches will change, and they turn blue at times, but they are generally in the same area.

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