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Scanning Double-8mm at 24fps


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I've been shooting Double-8 film at 24fps on my newly refurbished Bolex P1. When I had two rolls scanned by a very reputable service using a ScanStation, they had a problem outputting the digital file at the correct frame rate. I had clearly indicated in the order that the film was shot at 24fps. The first time the output ran fast, as if 24fps was playing at 33fps (8mm at 24fps runs at 18ft/min and 80 frames/foot) They worked hard to correct this, but the second time the output ran slow, as if 24fps was playing back at 19fps. The third time they got it right, apologizing that getting things right in 8mm was tricky and they had now found the correct formula. Unfortunately, the next two rolls I sent them again came back speeded up. I can correct things in Final Cut by slowing down a clip but the results are a bit jerky and it defeats the whole purpose of shooting at 24fps to smooth things out (as opposed to 16 or 18fps which used to be what 8mm was normally shot at). I'm assuming that this is a software issue and not related to whatever scanning rate the ScanStation uses to capture the film. Is there any information that I should be adding to my instructions to help them get things right the first time? 

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The Scan Station should just output a 1:1 film frame to video frame in Quicktime and then the Scan Station has settings for what it tells the metadata in Quicktime to be. Quicktime can playback at a range of framerates and the metadata should be set to play the film at 24FPS so it plays 1:1 what was shot to the digital playback.

Keep in mind that unless your Bolex has been modified with a crystal sync motor the mechanical governor will not film at an exact speed and it will be variable from things like how much wind on the spring and ambient temp etc.

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Robert, thanks for explaining how the setting between Scan Station and the Quicktime output should work. Fortunately this is film, so it's easy to count the actual number of frames in a clip on a light table and compare that number with the duration of the clip in the Quicktime file. I chose a clip in which people walk across the frame. On the light table that clip was 166 frames long or 6:22 seconds at 24fps, which feels about right based on my recollection of taking the shot. In the Quicktime file the clip is 3:10 seconds long or 82 frames at 24fps. The action is clearly speeded up and the film frame to video frame ratio is definitely not 1:1; it's almost exactly  2:1. So what are they doing wrong and what do they need to adjust to get the ratio right? The Quicktime file name says 24fps.

While I understand that a wind-up Bolex won't run exactly at 24fps, in this case the problem is not with the camera.

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That is just bizzare then, the Scan Station has a drop down menu in the settings for playback framerate and they have some 18 into 24 or 16 into 24 settings and then there are 16fps 18fps 24fps etc. settings.

If the Scan Station is working properly (it probably is if it is scanning film) then they should just select the 24fps playback framerate.

The odd 18 into 24 etc. type framerates in the dropdown menu might be the culprit. Otherwise I am as confused as you are because there should be a 1:1 film frame to Quicktime frame scan at 24.00 fps.

 

 

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The other thing I wonder about is whether the oddness of unsplit Double-8 is a factor--you're scanning 16mm film, but there are two sets of images, one running forward and the other backward. I have no idea whether both images are scanned together or separately (one half of one roll was output flipped--easy to fix in Final Cut). In any event, these are good people and I'll get back in touch with them to discuss the problem. I was just getting frustrated by the back and forth, and was hoping to better understand what might be causing the problem so that I could give them clear direction on how to fix it. Your explanation that they should be able to output 1:1 at the 24fps setting (rather than 16 or 18 to 24fps) helps.

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Oh well if it is unslit then it is scanned as 16mm and each frame has 4 R8 frames in it.

I know our Scan Station has issues with scanning unslit R8 as it is "looking" for perforations to lock onto to stabilize and that is an entirely automatic process in the Scan Station.

Did you want the 4-frame look? Is that why the film is not slit and assembled as a 8mm roll?

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It was the vendor's choice to process and scan the negative film unslit. Does Cinelab normally slit Double-8 negative film prior to scanning? I thought it was standard practice not to (since it can't be projected like reversal). I think they had come up with a formula to lock onto a frame of unslit 16mm at 16fps, but I gummed up the works by shooting at 24fps, requiring a new formula. Maybe the easiest solution in my case is to go ahead and slit the film.

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We offer the choice of either leaving it as 16mm or slitting it and making a single strand R8 reel.

Honestly if I had to do all that post work to try to turn unslit R8 into single strand scans I would charge $200 a roll to scan it and we charge $25 for 2K and $50 for 4K scans of slit R8.

usually when R8 is left unslit it is because our customers want the quadrant look.

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I agree with you entirely. I now understand that it only makes sense to specifically request the film to be split: it's more cost-effective for the vendor and it's going to make it easier to output the frame rate that I shot at. Thanks for taking the time to talk me through this. I also appreciate that you're pricing Double-8 the same as Super-8. I'm beginning to think that there are some real advantages that Double-8 has over Super-8: 1) mechanical cameras that can be refurbished, repaired and maintained (the electronics on most Super-8 cameras exceeded their life-spans a long time ago and often cannot be repaired; 2) essentially the same film stocks are now available for both formats; 3) the pressure plate on a Double-8 camera is inherently superior to the flawed design of a Super-8 cartridge, yielding better registration. I mostly shoot 16mm, but when it comes to fun stuff I'm sticking with my Bolex P1 until someone comes out with a Logmar-type Super-8 camera with sprockets that thread the film through a gate with a pressure plate.

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We see allot less Double (Standard) 8mm than Super-8mm and so turnaround times for Std-8 are longer and slitting is labor intensive especially with the softer thicker emulsion of ECN. It can be a great format like you said with more mechanical simpler cameras.

We have also been supporting the UltraPan 8mm which is like techniscope 2-Perf for 16mm as it shoots the Std-8mm roll once but is widescreen across the gauge.

Also Std-8mm stocks are a little harder to find and more expensive for color.

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Posted (edited)
On 5/19/2021 at 10:49 PM, Robert Houllahan said:

Oh well if it is unslit then it is scanned as 16mm and each frame has 4 R8 frames in it.

 

It is not, at least, not on the ScanStation. The ScanStation can scan unslit 8mm - you install the 16mm gate, but you select Double 8mm when loading the film. It repositions the camera accordingly, and only scans down one side of the film. Then you move the film from the takeup side over to the feed side, and run the other half. 

The frame rate thing is weird. I'm going to go out on a limb here and say that whoever is using this machine has no idea what they're doing, or maybe it's a ScanStation Personal and that machine can't do this and they had to come up with some weird workarounds (I don't know, but it could be the case. We have the full ScanStation and it does do this. It was a request I personally made with Lasergraphics years ago, that they implemented).

Setting the frame rate honestly couldn't be simpler - as Rob pointed out, there's a pulldown with all the available frame rates. So unless they're doing something weird like not scanning directly to the format you want and then doing some kind of post-scan frame rate conversion outside the ScanStation, I don't really see why they can't just scan it at 24. 

On 5/19/2021 at 10:30 PM, Serge Gregory said:

The other thing I wonder about is whether the oddness of unsplit Double-8 is a factor--you're scanning 16mm film, but there are two sets of images, one running forward and the other backward.

Do you mean that your resulting file has both the forward and backward image? If so, unless you asked for that, that's being done wrong. I believe there's also an option to do that (you would use the Ultra Pan 8 setting, which would scan one frame that's the entire width of the 16mm film. In that case you'd see forward and backward frames, but the resolution of each of the frames would be about half of the resolution you'd get if you loaded it as double 8mm (because the camera/lens position is different for D8mm). 

 

On 5/20/2021 at 12:48 PM, Serge Gregory said:

I agree with you entirely. I now understand that it only makes sense to specifically request the film to be split:

There is no need. We scan unslit double 8mm and do so all the time. Works great on the ScanStation, and the end result is the same as scanning slit 8mm. Costs the same as scanning regular slit 8mm as well. 

Edited by Perry Paolantonio
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Very interesting, Perry. Thanks for the clarification. What I've learned from this thread (and my unfortunate experience) is that there is no "industry standard" for handling Double-8. Filmmakers submitting their work better be sure that the lab process (slit or unslit) and the scanner capabilities are in sync. Personally, if as Rob says that slitting is a pain (especially with an ECN stock), I would prefer to go with a scanner that can handle unslit Double-8--less chance of damaging the original.

No, my file didn't have the footage running forwards and backwards. I was just trying to describe what processed Double-8 film physically looks like. It was bad enough that the frame rate was off and one roll had the footage flipped.

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3 minutes ago, Serge Gregory said:

No, my file didn't have the footage running forwards and backwards. I was just trying to describe what processed Double-8 film physically looks like. It was bad enough that the frame rate was off and one roll had the footage flipped.

If I had to hazard a guess - I'm thinking they scanned the film as 16mm, then used software to separate the two halves, then the two stacked images that resulted from that. You could do this in something like AVISynth, or Open CV or something like that. But the way to do this correctly if you're going to go that route, is to make your intermediate files into an image sequence. Then you can bring that into Resolve or some other NLE and define the frame rate that it would be output to. That's kind of the only way I could see winding up with really weird frame rates. The more convoluted the process the more likely you wind up with a wacky result!

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