So what’s this all about?
When restoring film footage digitally, it can be an advantage to understand the films physical qualities prior to being digitised. As an example, film gauge is a quality that defines the films physical width, which in turn provides hints to the image quality such as grain size and resolution.
In part one of this two part article, we explore the smallest film gauges and work our way up to super 16mm. In part two we will look at the various forms of the industry standard 35mm as well as looking at a couple of common larger formats that you may come across. Throughout both articles, I will be using 35mm Academy 4 perf frame for a size comparison. In each case I will be referring to the camera original neg / reversal areas, which is the ideal starting point for a digital restoration, rather than process or projection areas.
In a future article we will be looking at the different process stages of film and how this too can effect your restoration and whilst this isn’t a comprehensive list, it will provide you with a useful understanding of the most common film gauges.
Standard / Regular 8mm / Double 8
Main usage: amateur / distribution
Measuring a tiny 8mm wide this motion picture format was first released back in 1932 by Eastman Kodak. It is sometimes referred to as Standard 8mm, Regular 8mm or double 8 and the main purpose of this format was to provide a cost effective alternative to 16mm for amateur film making and distribution during the Great Depression.
Interestingly this film gauge is actually 16mm film with double the perforations down each side allowing the user to expose half the frame, then flip the spool and expose the other half. In practice flipping the spool needed a bit of experience so as not to flash the film. But it was certainly an interesting way to extend the run time from a single 16mm roll by exposing four 8mm frames in the space of one 16mm frame.
It’s unusual to see the film in its native state due to the fact that when the film was sent to the lab, it was processed, slit it down the middle and spliced together to form a single reel of standard 8mm. There was another less common format called straight 8, which was pre-cut.
With a very small camera aperture of 4.5mm x 3.3mm the images produced by this format are very grainy and usually quite soft due to the vintage lens designs used for capture. Optically resolving fine detail in such a small area is a challenge even today. Thanks to the fact it uses a 16mm transport, the familiar gate weave that is synonymous with super 8 is far more controlled with standard 8. Due to this being an amateur format, camera’s sometimes weren’t maintained to the same level as a professional camera and as such are prone to issues such as tramline scratches and gate hairs. Film burn is also fairly common due to the way the spool is loaded.
Main usage: amateur / distribution
Developed as an idea during the early 1960’s and released in 1965, super 8 was designed to provide an easier to use, better quality variant to the ageing standard 8mm format. Super 8 still uses the 8mm film gauge but uses more of the films surface area to expose at 5.46mm x 4.01mm vs 4.5mm x 3.3mm of the standard 8mm format which was achieved by drastically reducing the perforation size. Unlike 8mm, super 8 is cartridge fed making it a much easier to load and more accessible to the end user. Super 8 also offered the ability to take a sound track between the edge of the frame and the edge of the exposure area.
As with 8mm, Super 8 has a very small exposure area when compared to something like 35mm and because of this also suffers a large visible grain structure. That said, when using a comparable film stock, and scanned to the same resolution it is a slightly finer grain when compared to standard 8mm. Super 8 cameras and optics were generally mass produced and while some had outstanding mechanisms, a lot were very cheaply made, suffered from softness from poor optical design and incredible instability in the film transport.
Because of the point and shoot nature of super 8, people quite often did not check the film gate for debris. Scratches are also a common sight with this format.
Main usage: amateur / distribution
Introduced by Pathé in the early 1920’s, 9.5mm was intended primarily as a distribution format for the projection of films in the home. Due to the fact the format was easy to use and inexpensive, it rapidly became popular. Not long after it’s release a camera system became available allowing for amateur film makers to shoot with the format and is more common than you would think, especially in Europe. Mostly reversal film stocks were used with the camera.
The format used an unusual single perforation between each frame, which was a departure from other amateur and professional formats of the time which employed perforations on the side(s).
Although unusual, this design had a fairly significant benefit as it allowed for the area on the sides normally taken up by perforations to be used for picture. Given that the format it is only slightly larger than 8mm, it manages to cram in an image of 8.2mm by 6.15mm which is impressively just shy of the exposure area of standard 16mm.
The format slowly went into decline after the release of 8mm in the early 1930’s despite the fact 8mm was considered to be an inferior format. By the 1960’s the format was no more, only being kept alive by enthusiasts. Most examples of 9.5mm are in generally very good condition which is perhaps a testament to the design especially when compared to other film gauges of a similar vintage.
When scanned at a similar resolution to 8mm, 9.5mm has greater fidelity and has a tighter grain structure but it does however, suffer from the same common problems as those formats such as gate weave and blemishes like scratches and dirt covering a significant part of the image due to their relative size to the aperture.
Main usage: Industrial films, documentary, news gathering, broadcast
Standard 16mm was introduced by Eastman Kodak in the early 1920’s. Initially the format was intended for amateur use as the film gauge was considered to be inferior quality to and hence not suitable for, professional applications.
Having proven popular, during the 1930’s the format was later developed with the addition of a an optical sound track on the edge of the frame. The format went on to prove it’s worth extensively during world war two and became the go to format for many industries post war thanks to it being a low cost and high quality alternative to traditional 35mm.
For television the cost benefit was particularly advantageous. In the period from 1960 to the1990s, 16mm was used in television especially by the BBC in the United Kingdom who worked extensively with Kodak to refine the format, and found great use for it particularly for location shoots. Because of this 16mm is a format you will likely come across in abundance in your archival restoration work.
Measuring 16mm across with two perforations either side of each frame line when using double perf stock, the 10.26mm x 7.49mm camera aperture offered far superior quality to that of 8mm.
Standard 16mm having found its place in many professional environments, was used with high quality camera equipment and optics. This is why much of the footage shot on 16mm is sharp, well exposed and stable. When using a comparable film stock and scanned to a similar resolution the grain structure is much tighter and more refined than that of 8mm formats. Additionally there were higher quality colour negative stocks available for 16mm that weren’t available for 8mm. The format is also less prone to the artefacts you might see with poorly maintained amateur camera equipment.
Main usage: modern broadcast, feature films, commercial
In 1969 Rune Ericson developed a new variant of the 16mm gauge designed to maximise the exposure area of the film. Standard 16mm has perforations on both sides of the film to allow registration pins in the camera to position the film correctly in the gate. Whilst some 16mm cameras used registration pins for both sides of the film, quite a few 16mm cameras only used one and some in fact used no registration pins at all. Ultimately it was deemed that using a single registration pin had no detrimental effect to the resulting images and that the space used for the perforations on one side of the film was a waste. By removing the soundtrack area, perforations and widening the camera film gate it allowed the user to record a larger 1.66:1 ratio image onto the same 16mm film gauge and thus super 16mm was born.
Initially this 1.66:1 aspect ratio meant it was more suited to feature films where it could be blown up to 35mm and presented in its native ratio or with minor amounts of cropping at 1.85:1. 16mm was still favoured for a while in traditional broadcasts because it matched the 1.33:1 viewing format and super 16mm offered no distinct advantage. However with widescreen future proofing in mind and with the advent of HDTV broadcasts on the horizon, film makers ultimately began to shift to using super 16mm to take advantage of the extra area the format provides.
Measuring 12.52mm x 7.41mm Super 16mm offered approximately 21.5% more exposure area over standard 16mm. Of course this added exposure area only became an advantage when presenting the format in 1.66:1 or 1.85:1 aspect ratios and where an equivalent piece of standard 16mm would have had to have been cropped severely to match it.
Super 16mm offers very similar image quality to standard 16mm. Grain structure is fairly coarse compared to 35mm, but has an aesthetic which has become popular with modern film makers, who are after the characteristic film look while maintaining a level of control over the image. Super 16mm was and is still used with well maintained professional cameras and optics. Artefacts and damage on the surface of the film will appear worse compared to 35mm scanned at a similar resolution due to the magnification. In general gate weave is superior to the 8mm formats but stability is still not quite as good as 35mm.
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