Tuesday, January 1, 2019

Basic Reference Guide to Movie Restoration

1. Films
2. Transfer (Digitizing)


1. Films

First and foremost, film reels used to shoot movies are vertical, not horizontal like the header of my blog which is film for still camera.

Here are the most common types of 35mm film format used to shoot movies.

- Cinemascope 4-perf (2.35) Anamorphic Cinematographic Process

- Widescreen 4-perf (1.85) Spherical Cinematographic Process
- Super35 3-perf (1.85) Spherical Cinematographic Process
- Techniscope 2-perf (2.35) Spherical Cinematographic Process


As can be seen in the picture above, there is 2 different ways of shooting a 2.35 aspect ratio movie.

1 - Cinemascope 4-perf (Anamorphic Cinematographic Process)

2 - Technicope 2-perf (Spherical Cinematographic Process)

Cinemascope vs Techniscope


Interesting fact---> Since Techniscope (2-perf) was cheaper than Cinemascope (4-perf), a lot of exploitation films were shot Techniscope for budgetary reasons. In other words, for your 400 feet reel, you get twice the number of frames with a 2-perf reel as opposed to a 4-perf reel.

Interesting fact---> Cinemascope has twice the vertical resolution as opposed to Techniscope.


Interesting fact---> Cinemascope and Techniscope both offer a different look.

Spherical Cinematographic Process Lens Flare Signature (1)

Anamorphic Cinematographic Process Lens Flare Signature (2)

Before talking about digitizing, one must know what elements can be digitized.

- Cut Negative which is made of the OCN (Original Camera Negative)

- Answer Print
- Interpositive
- Internegative (Dupe Negative)
- Release Print (Projection Print)

Not sure what are these, please have a look at the following Kodak Optical Workflow chart. For the whole Kodak .pdf document, please click here.



Important---> The optimal source to digitize is the Cut Negative as every time you create a copy in the optical world you loose detail, loose color fidelity and you add more grain.

Important---> You can't watch a negative as the colors are inverted, you have to do a positive copy in order to watch the Cut Negative. This is what the Answer Print is for. It is a positive copy of the Cut Negative.

Important---> When you shoot a movie, it is quite possible to have to shoot a scene over the course of many days which can lead to unbalanced shot to shot when watching the first Answer Print iteration.

Important---> Believe it or not, they used to do Color Correction in the optical world (in a laboratory) so the shots match. Deliverance's famous day for night sequence was originally done that way too.

Important---> When satisfied with all the color correction from screening let's say 6 iterations of Answer Prints, the final Answer Print is labeled Interpositive. Could it be use as a reference when restoring the movie from the OCN? I bet it could!

Ok, now I'm confident you guys understand that the OCN  are not color corrected and that an Interpositive contains all the color correction as well as any additional optical work, things  like superimposed credit at the beginning of the movie for example.

Basically, the Interpositive is a second generation copy, it is a positive copy and it's the finished movie.

Important---> An Interpositive has 2 layers of grain, one from the OCN and one from the Interpositive itself. An Internegative has 3 layers of grain, one from the OCN, one from the Interpositive and one from the Internegative itself. Same thing goes for a Release Print (Projection Print) which has 4 layers of grain since they're next in the chain.


2. Transfer (Digitizing)

Film elements can either be digitized using a process called Telecine or by a process called Pin-registered Scan.

Open Gate Pin-registered 2K Scan of Techniscope Film (3)

A Telecine is limited to 1920x1080 and is done in real time. The resulting transfer ends up on a digital tape (HDCAM SR). The tape is then digitized to files like .mov (Prores 422 HQ) and sometimes to .dpx.

A Pin-registered Scan can either be 2K (2048x1556), 4K (4096x3112). A scan is usually done pin-registered (this stabilize the film a lot) and can take many seconds just to scan one frame.

Pin-registered Scan leads to better details. The grain structure will also be smaller and more refined with a scan.

Since the quality of scanned film is superior to the quality of a Telecine, therefore a Telecine is cheaper than a Pin-registered Scan.

The grain of a Telecine will most of the time end up being bigger than the grain of a Pin-registered Scan.

Some brands of Telecine equipment can result in noisy digitized files and images rendered with a non-organic texture. A good example of that would be the Telecine done at LVR Video in Italy. I would describe the texture as if you were watching the movie through a screen door just like in the picture below. I must admit the texture is less obvious in motion but still, it's there.

Non-organic LVR Video Telecine Texture (4)

Here's a frame that shows how the texture of a 2-perf Techniscope movie should look like when digitally transferred. Whether you like it or not, this is how film looks when properly scanned.

Organic 2K Pin-registered Scan Texture (5)

Interesting fact---> 2K or 4K? Well, in the past few months I've read many posts where people complained about movies being scanned at 2K rather than 4K. Ok, from 2003 to 2012, I happened to work in the visual effects industry as a Digital Compositor for movies shot on 35mm and the resolution of the scans always was 2K. In the early nineties, engineers working for Kodak came up with a file format named Cineon and concluded that it wasn't possible for a human eye to distinguish film that went digitized then printed back on film from the raw film when projected on the silver screen. To me, 4K is kind of just to make sure you're really not loosing anything.

Interesting fact---> Grain should be judged in playback as on a still it might appear twice as big as it actually is. You also need to be at 1:1, not zoomed in, not zoomed out, 1 pixel from the image = 1 pixel of your monitor.



References:

1. Frame from Nightmare City Blu-ray, UK, 2015, Arrow Video (FCD1112)
2. Frame from The Fog Blu-ray, US, 2013, Shout Factory (SF 14172)
3. Frame from the "Restaurationsvergleich" extra from Don't Torture a Duckling Blu-ray, Germany, 2015, 84 Entertainment (8731)
4. Frame from the European Cut of Dawn of the Dead Blu-ray, Japan, 2013, Happinet (BBXF-2062)
5. Frame from What Have You Done to Solange Blu-ray, UK, 2015, Arrow Video (FCD1198)