Advice on 8mm TK format for cinema exhibition

[Matt Kemp]

Hi All,

 

I recently shot a feature on Ektachrome 64T, and have sent it for scanning at a TK facility in Eindhoven.

 

Thing is, at the same time I took the 250 or so rolls for scanning, I also picked up five or so test rolls I had shot beforehand. While the scan quality itself is excellent, the files I received back are in a non-standard format, basically a BMP image sequence, with each frame dimensions 1220x860, wrapped in an .avi container (and a massive 47Gb for ten minutes of film..!)

 

I can of course convert these files into any standard video format for editing and exhibition, but as someone much more at home in the analogue world, I was really hoping someone here might be able to give me a bit of advice on the best format to convert the files to.

 

I have created test exports using the DVCPRO HD codec, the 422 10-bit uncompressed codec, and with various flavours of XDCAM and HDV formats, but am still at a bit of a loss as to which to proceed with. I realise of course that the whole process also depends a lot on the ultimate delivery format, which I envisage will be HD on either XDCAM or SR tapes for cinema screening.

 

I apologise in advance if this post brutally displays my lack of insight into the digital post production workflow, but any help or advice would be greatly appreciated.

 

Thanks,

 

Matt

[Adrian Sierkowski]

I'd go for ProResHQ from which you can go out to HDCam for exhibition if need be or D-Beta.

 

I've worked ProRes into most workflows these days for both lower end HD work and higher end film work. Normally the process looks like this:

 

for HD

 

Shoot and edit natively. Export as ProResHQ from which we print to HDCam for a tape to tape.

 

For film:

Shoot and process, best light to ProRes, Edit-->EDL--> telecine/correct to HDCam (or HDCamSR), Recapture ProResHQ for SD/DVD Digital deliverable (DVDs/BluRay/Web). Use HDCam or HDCamSR for SD tape downconvets (D-beta normally).

( I go with the ProRes workflow like this as opposed to a more typical DVCam workflow just because it avoids another deck rental. Of course, this requires digital backups and I highly recommend LTO Tape for any Data-Centric workflow.)

[Matt Kemp]

Hi Adrian,

 

Thanks very much for the reply, very useful.

 

If I can ask, do you choose that format based on a quality/practicality compromise? For example if equipment or software were no object, would you still choose it?

 

Thanks again,

 

Matt

[Adrian Sierkowski]

Yep, it's why I go with the ProRes, it's basically the best I've found one can deal with, else I'd be working with Uncompressed HD 4:4:4 video data... or larger... but I don't think that's happening anytime soon.

[Matt Kemp]

Thanks again for the reply.

 

I found out from production today that the actual plan is to edit the TK'ed footage and then blow up to 35mm direct from the digital file for cinema exhibition.

 

In your opinion does that mean I should create an uncompressed 4:4:4 master from the original image sequence, edit offline at a lower resolution, conform the uncompressed master to the offline EDL and use that to print to 35mm?

 

I get the feeling I'm really missing some basic foundation of knowledge with these issues but, as always, any advice appreciated.

[Frank DiBugnara]

In your opinion does that mean I should create an uncompressed 4:4:4 master from the original image sequence, edit offline at a lower resolution, conform the uncompressed master to the offline EDL and use that to print to 35mm?

 

Matt,

 

I think that is exactly what you need to do. The image sequence does not have any metadata so adding the step of converting the sequence to some sort of uncompressed 444 color space which will provide a path back to itself from the lower-res offline is the way to go. Some of the latest Pro Res flavors are excellent---but not for outputting to 35mm.

 

Are you doing the final color correction yourself? You'll want to make sure whoever does uses the proper LUTs along the way. I get the feeling this is where most film outputs fail.

[Matt Kemp]

Thanks for your post, Frank.

 

Again, excuse my ignorance but what do you mean by 'LUTs'?

 

The grade and output to 35mm will be done at Cineco Amsterdam, using their Nucoder Filmmaster.

[Frank DiBugnara]

A LUT is a "Look Up Table".

 

In short, everything that happens to your image from the moment it leaves your on-line conform/color correction and ends up on the 35mm IP or IN is going to have an impact on the image. There are many variables here, but the biggest are the characteristics of the film-out device and the film stock itself. LUTs allow you to compensate for the changes that are going to be introduced between the online-conform and the 35mm output. Without accounting for these changes, you can be sure that what you see on your HD monitor in your online suite is NOT what you are going to see when you watch the print.

 

So a custom LUT is often created and then applied as an "adjustment layer" in color correction. I've heard them described as "magic sunglasses" that are temporarily put onto your image as you color correct. These sunglasses show you what the image is going to look like on film before it gets to the film, taking into account the variables introduced in the film-out path. Your color correction decisions are therefore based on what the image is GOING to look like in the end.

 

When you finish the color correction you remove the adjustment layer before delivering for film-out. Again, I am learning that this step is completely messed up on a regular basis. I was not sure from your post how much of this you were going to do yourself---seems like you'll probably have some experienced people associated with the Filmmaster to help guide you.