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This blog has been silent for two years, but progress on this restoration project has been on-going, albeit with some significant pauses due to other demands on my time. As of April 2017 we had reached a satisfying conclusion to the problem of stabilising the jitter in “Marianne”, the 1963 Tarax Show Christmas Pantomime which is the subject of my current focus. For practical purposes the jitter was eliminated, but the problem of dust and scratches remained.
Having spent the previous six posts explaining the jitter stabilisation process for the 1963 kine of Marianne, let’s take a look at how well it works. So that you can see the jitter more clearly, I’ve prepared a 30 second sample video which shows a side-by-side, before-and-after comparison. As explained earlier, this kine was scanned at 2K resolution, which is 2048 x 1556 pixels. The jitter detection and stabilisation was also done at this full resolution for maximum accuracy.
For those of you not completely bamboozled by this excursion into the very-technical, here is a summary of the whole stabilisation process developed for the Marianne kine scan. Convert the 2K scanned video into a series of tif files, one file per frame. There are 79675 frames, the dimensions of each frame being 2018 x 1556 pixels. Divide these frames into sequences roughly corresponding to scene changes in the production.
In this post we look at a few odds and ends that arose during the stabilisation exercise: Dealing with frame defects and splice bumps, adding frame numbers, and re-combining frames into a video file. Dealing with Frame Defects An unexpected challenge which arose when stabilising the thousands of frames in each sequence, was that some frames had defects which obscured one or more white corner dots and made it impossible to measure the movement of these corner dots.
The last post described using image correlation to measure the motion of the white dots in each of the four frame corners. These white dots move together with the video raster. Stabilising the white dots will stabilise the unwanted movement or jitter of the video raster. The following graphic used in an earlier post demonstrates again the three kinds of motion and the red arrows show the corresponding offsets of the corner dots.
In the last couple of posts dealing with “Home-Grown Jitter Stabilisation”, we established: The jitter comprises displacement, rotation and vertical scaling. There is a white dot (partially) visible in each of the four corners of each scanned film frame. These dots move together with the video raster. If we can measure the frame-to-frame movement of these dots, we can calculate and then correct (i.e. remove) the jitter. So now we come to the topic of how to measure the frame-to-frame movement of these white dots.
Let’s put some visuals to this idea of stabilising the jitter in the kine scans. As I mentioned in the last post, the jitter actually comprises three kinds of motion: Displacement Rotation Vertical stretch The following three diagrams illustrate each kind of motion. To make them clearly visible, the movements in these illustrations are proportionally much larger than in the actual film frames. For each kind of motion, the little red arrows show the resulting movements of each corner artefact — the white dots which are stable relative to the video raster.
As mentioned in the previous post, Promoscape had been unable to deal with the jitter: “With regard to stabilisation, we can’t find a cost effective and consistent way to achieve this with the footage.” They explained that the jitter was not just horizontal and vertical movement (displacement) but included rotation as well. I’ve talked about possible sources of this jitter in the post Assessing the Scans Part 2 — Jitter.
Twice before we’ve looked at digital restoration options: Exploring the Possibilities of Digital Restoration: Shows a digital restoration test of some Tarax Show kine footage done by Lowry Digital Imaging in Burbank, California. Experiments in Digital Restoration with PFClean: Covers my own experiments with PFClean from The Pixel Farm in the UK. Each of these tests produced promising results, but the cost of a full-length restoration was prohibitive. Were there any other options?
In the previous post we established the downsampling ratio for the 2K scans of “Marianne” (1963) which would result in a PAL SD frame — after cropping off the overscan. Downsampling the 2K Scan Why downsample the video at this stage rather than doing positional adjustments, grading and repairs at 2K resolution? The fact is, there’s not really any benefit in retaining all that resolution when the original analog video raster recorded to film had a resolution of roughly 300 lines vertically by perhaps 500 lines horizontally (see earlier posts for a more detailed discussion of this).
In the earlier post about downsampling the kine scans from 2K to “PAL SD+”, we established the need to know the minimum dimensions of the video raster, which varies slightly in width and height over the duration of a reel. The final cropping boundary for a PAL SD video needs to fall within the minimum video raster size so that we get nice clean edges on the video frames.
Wow, we’re up to the 23rd post in this blog series on restoring the Tarax Show Christmas Pantomime kines. Let’s take a breather and review where we’ve been so far and then map out the next steps. Where We’ve Been So Far Here is a chronological list of the posts so far, grouped under headings. Each title is linked to its post (in case you want to go back and read any you missed).
Congratulations if you got through the previous rather technical post about Pixel Aspect Ratio. The next question is: how does this Pixel Aspect Ratio business affect the process of preparing these kine scans for DVD release? Pixels Are Inherently Shapeless When stored in a digital file on disk or DVD, a video frame is just a series of numbers, where each number (or set of numbers) describes the brightness and/or colour values of a pixel — a video frame being a 2-dimensional array of pixels.
I mentioned in the previous post that we would talk about Pixel Aspect Ratio (PAR). In this post we’ll talk about the historical background and in the next post we’ll look at how it affects video downsampling for this project. Wikipedia provides a good introduction to PAR: Most digital imaging systems display an image as a grid of tiny, square pixels. However, some imaging systems, especially those that must be compatible with standard-definition television motion pictures, display an image as a grid of rectangular pixels, in which the pixel width and height are different.
In the previous post we established the need to downsample the high resolution 2K scans to a lower resolution for PAL SD release. We need to adjust this downsampling so that: The overscan (i.e. the area of the film frame beyond the boundaries of the video raster) is preserved. The dimensions of the video raster (after downsampling) are slightly larger than the PAL SD frame size of 720 x 576 pixels.
As I write this blog post (November 2015), I’m still covering work done a year or more ago. At the time I didn’t think to write about it. Looking back though it seemed an interesting journey. So let’s see, we’ve covered preparatory work before scanning, various attempts and experiences with scanning the kines, some more successful than others, an analysis of the scans and some experiments with digital restoration.
Some years ago there was a television series called “The Second World War in Colour”. It featured seldom seen colour film footage taken during the war. In the introduction to the accompanying book (of colour photographs) the author remarks that there is a widespread and unconscious perception that “…the war was fought in black and white” — a result of the fact that most of the historical newsreel footage and photographs are in black and white.
Having assessed the four Tarax Show Christmas Pantomime kine scans, it is time to plan out a restoration roadmap. Restoration Steps The steps now required to restore these scans ready for release on DVD are (not necessarily in this order): Stabilisation of jitter if possible and practical. Tests have shown jitter can be most accurately measured and corrected at high resolution. Downsampling of the scanned frames to PAL SD+ resolution — this means PAL SD resolution (720 x 576 pixels) plus allowance for the overscan.
In the previous four posts, we assessed four aspects of the Tarax Show Christmas Pantomime kine scans: Anatomy of a Kine Frame Jitter Video Levels Soundtrack The most significant problems were jitter and dust and scratches. We will look at ways to reduce the effect of these in later blog posts. However, the scan of The Golden Princess done on the Spirit Datacine suffers rather badly from some of the defects to which “line scanners” like the Spirit are susceptible.
In assessing these kine scans we come finally and briefly to the sound tracks. Each kine has an optical soundtrack, some are variable area, others variable density. Optical soundtracks on 16mm film are not exactly “high fidelity” audio. The two most significant limitations on quality are: The frequency range. The soundtrack is recorded linearly along the edge of the film. The limitation on frequency response is the shortest wavelength which can be recorded and reproduced.
This post discusses video levels in the four kine scans. For the purposes of this discussion, we will talk about luminance values only since the Tarax Show scans are black and white and the colour information has been removed from the scans. First, let’s look at a screenshot of a “video scope” and the corresponding frame, as displayed in Final Cut Pro. A frame from one of the kine scans together with a video scope display that plots the luminance values in each scan line.
What I’m calling “jitter” is unwanted rapid small movements of the video image vertically and horizontally caused by the mechanical processes of recording to and reproducing from film. By scanning an area of the kine film frame beyond the edges of the video raster, one can get some insights into the sources of jitter. Jitter on the Spirit Datacine The Spirit Datacine seems to be particularly susceptible to jitter. It scans the film while it is moving using a “line scanner” and attempts to detect the location of each frame by sensing the position of the sprocket holes.
With four scans under our belt, let’s take a look at them in more detail as an aid to planning how best to restore them for DVD release. The first thing to note is that all four scans have “2K” resolution — 2048 pixels wide by 1556 pixels high. That’s a lot more resolution than is needed to reproduce the detail on the film. As explained in an earlier post1:
As I mentioned in the previous post, one kine reel had a noticeable “vinegar syndrome” smell. The Australian National Film and Sound Archive describes the problem: “Vinegar syndrome is a term used to describe the chemical reaction that goes on during the deterioration of cellulose triacetate film support. The presence of the odour does not mean the film has degraded, but rather that the reaction is taking place.” Vinegar syndrome causes shrinkage of the film base — this appears to have happened to the 1959 kine of “Merry Make-Believe”.
It was with excited anticipation that I returned again to Cutting Edge to see first hand the high resolution scans of the Tarax Show kines. With high quality, high resolution scans from the film, the project to restore these productions for DVD release could now move forward. Justin had scanned all the reels sent, except for “Merry Make Believe” (1959), which was warping and jumping off the Spirit Datacine motion-sensing sprocket and losing registration.
Having found a Spirit Datacine in Brisbane and tested some of the Tarax Show kines, it was time to prepare the full length 16mm reels for scanning. Of the five Tarax Show Christmas Pantomimes that I had fully on film, I chose four for scanning: 1959, 1961, 1962 and 1963. In addition to the full reels, there were some cans marked “offcuts” which suggested that pieces had been excised for use in the “Magic Box” show about early television which Denzil Howson presented in his later years.
The discovery of a Spirit Datacine at Cutting Edge in Brisbane, only two hours away, was a relief after the at-a-distance negative experience with the Sydney company. This time I could see the equipment for myself, and discuss in person what was needed. So in March 2013 I arranged to visit Justin at Cutting Edge, to see the Spirit machine up close, and to discuss the process for having films scanned.
When the Sydney telecine company failed to deliver a useable scan, the search was on again for a quality film scanning service. I called The Post Lounge again. They told me they were closing their Gold Coast facility and not running the Spirit Datacine anymore. They were planning to sell it. Apparently there was very little production happening at the Gold Coast and future productions would probably be all-digital, without using any film at all.
It was not until 2012 that I was able to find time to arrange telecine transfers of the full length reels of the Tarax Show pantomimes. However, things had changed drastically in telecine land since the Spirit Datacine test done by Larry at The Post Lounge in 2008. Firstly, Larry had departed some years earlier and had not been replaced by another full-time telecine operator. The Post Lounge were now operating their Spirit Datacine on an as-needed basis using staff from their Brisbane office.
The black and white television equipment installed at GTV9 in the late 1950s delivered remarkably good picture quality. This was especially so within the studio complex itself where the engineers maintained the equipment to a high standard and sought the best possible picture quality. Before the arrival of videotape in 1959, making “kines” to 16mm film was the only way of preserving a broadcast. The use of film as an archival and/or distribution medium continued well into the 1960s.
Around the same time as Studio One at GTV9 was transformed into Toyland for the last Tarax Show Christmas Pantomime, the BBC in London was getting ready to launch a new childrens’ television series about a curious character who travels through time and space in a police telephone box. Dr Who was also (mainly) a studio-based production, recorded to videotape and subsequently copied to film for distribution to television stations around the world.
In this post we’re going to get a bit more technical and look into how these film copies (“kines”) were made from the original television productions. We’re going to delve into some technical history of film recordings at GTV9 circa 1960. I would like to acknowledge the assistance of former GTV9 engineers Ian Douglas and Andrew McKean in providing technical details of the film recording system. Technical Parameters of the Australian Television System Circa 1960 The Australian black and white television system circa 1960 delivered 25 television “frames” per second.
In the previous post I gave a brief history of the Happy/Tarax Show annual Christmas Pantomimes. The surviving film copies of these are the subject of this current restoration project. Each one of the seven Christmas Pantomimes produced annually between 1957 and 1963 was recorded onto 16mm film. The resulting film copy is known as a “kinescope” or “kine”. For the 1957 and 1958 productions, recording to film was done at the time of live broadcast.
In 1956 the Olympic Games ushered Melbourne into the television era. My father (Denzil Howson) had joined GTV9 as Assistant Programme Manager in September that year and we were one of the rare households in those early days with a TV set. It was an American “Admiral” set and it cost a lot of money. The Happy Show premiered on 19th January 1957 — just two days after GTV9 began regular transmissions.
Having grown up in a family where filmmaking and film technology were a regular presence, I absorbed an interest in filmmaking and the technology of film at an early age. After working for many years in the field of graphic design and later web design, I inherited a collection of films made by my late father, some of which are of historical significance, in particular those dating from his work in the early days of Australian television circa 1956 to 1963.