Robert W. Paul – Films and Technology: Part Seven. That annoying flicker, a new camera, and The Last Machine?

1. Camera operator with Robert Paul camera, c.1902-3 and probably the final design. Possibly J.W. ‘Jack’ Smith. From John Munro, ‘The Science of Animatography. How “Living Pictures” are made’, Cassell’s Popular Science [Vol. 1], 1903. With thanks to Stephen Bottomore.
2. 1899 patent drawings: Figs. 1/2 were used in Reliance (and perhaps New Century) projectors and probably the later cameras, and Figs. 5/6 were used in the Century projector. There is no known application of the arrangement shown in Figs. 3/4, but perhaps it was used in a camera. The sprung ratchet with engaging knob L (Fig. 5, Century projector) quickly became worn with frequent use, causing problems. Further examination of surviving machines would help to refine the links between the patent drawings here, and the actual production machines. British Patent No. 487 of 1899.

‘Flickerless’ film projection, and shutter development

In 1898 Paul decided to try to design a new projector mechanism that would reduce screen flicker. With the novelty of ‘living pictures that move’ wearing off, and film shows becoming longer and more likely to induce eye strain, the long-suffered flicker was becoming a problem. The new intermittent design was used in the Century projector, c.1901 (and the New Century c.1902?) and a variation in its successor the Reliance projector, c.1902, improved 1904 and 1906/7.[1]

If you’d like an email notification of every new Optilogue post, why not Subscribe here?

The explanation of what Robert Paul attempted to do to reduce screen flicker is rarely described clearly, but it can be outlined in simple terms for those without technical knowledge. I will attempt to do so here.

When pulling down a frame of film in a projector, it must be blanked off from the screen or it would be seen moving down, as a blur. This blanking is performed by a shutter blade. The screen is therefore blank for part of the time; with a single shutter blade this happens 16 times per second, the speed at which films of this period usually ran. The ‘blank-picture-blank’ sequence on the screen causes flicker. It would seem intuitive to us – as it did to Paul – that somehow if the shutter blade could be reduced in size (area), the flicker would be reduced. Essentially, as far as flicker is concerned, a shutter is bad news.

3. Above: The three-slot wheel and sprocket part of the Century projector mechanism, from Paul’s 1901 catalogue (Cinémathèque Française). Below: The relative amount of light cut off by ‘other machines’, and the new Paul design, is shown here. The small degree of blanking given by Paul’s new design (Century and Reliance projectors) would, as claimed, have significantly reduced flicker, as well as improving picture brightness. From Paul’s Supplementary List of improved apparatus for Optical Projection, 1904-5 season (National Science and Media Museum).

In 1898 (patent application made in January 1899, marketed 1901) Paul tried to achieve this by making a three-slot mechanism (one version of the patent has a star-cross, but with three arms), which pulls the film down more quickly.[2] As a consequence, the shutter blade could be very narrow, reducing the blanking period on the screen and helping to reduce flicker.[3] This worked, but was stretching the limits of precision mechanics. Acceleration of the pin in the slot was very fast, and only a very finely engineered design would work smoothly, and if abused at all – quite common with the transportable projectors used in the days before fixed cinema installations – the machines could jam. There were other problems.[4] I shall let Robert Paul tell the story (from his perspective in 1904). The sales brochure promotes the advantages of the new ‘flickerless’ design, but also describes the problems encountered after marketing the first flickerless model:

‘A great step in advance was marked by the construction, in 1901, of the “Century” Animatograph […] and although the results were unanimously admitted by experts to be flickerless […] the wear on the locking device occasionally proved serious when the machine was in constant use for giving a considerable number of exhibitions every day. […] A large number of these machines were subjected to hard wear by their purchasers, with the result that valuable experience was obtained in finding out all the weak points. This experience, and that of the ten years [sic] which have elapsed since the manufacture of the first Animatograph, has been brought to bear in the re-designing of the whole apparatus, and the 1904 Model, called the “Reliance”, is now perfected.’

4. 1902 New Century projector. This model used a cast frame, an improvement over the sheet-metal ‘clock- type’ frame of the previous Century projector. No surviving example is known. Picture from Munro, ‘The Science of Animatography’, pp. 243-250 (Internet Archive).

The problems of running industrial machines of this kind, which were literally ‘hammered’ a thousand times a minute for many hours, daily, would not have been experienced by Paul in his scientific instrument business. Also, in motion picture cameras the amount of use is significantly less, and the problems would only become obvious with the punishment that long-running projectors suffered. One major change to the projectors was in the basic frame. Up until now, Paul’s projector mechanisms had been built around steel plates, in the old ‘clock maker’ style. With this arrangement, spindles going through the fairly thin plates were short, and it seems that with the extreme forces of a film projector the spindle holes (acting as bearings) were subject to wear. With the 1902 New Century Paul changed to a cast body, allowing longer spindle bearings and being generally more rugged.

Flicker could be addressed by another method, and Paul’s competitors did so, and here’s what they did.

With the shutter seen as an unfortunate necessity, it would seem counterintuitive to expect the addition of another shutter blade (two instead of one) to improve the flicker situation – but it does. A two-bladed shutter increases the flicker frequency from 16 per second to 32 per second (16 x 2 = 32 blanks per second) and the brain is less aware of it; essentially, the flicker is too fast to register intrusively. And with a three-bladed shutter, (16 x 3 = 48 blanks per second) the perception of flicker effectively disappears. So Paul’s competitors, in the early years of the 20th century, adopted the much simpler way to reduce screen flicker, by adding more shutter blades to a standard four-arm Maltese cross projector mechanism.[5] Some light was lost with the extra blades, but that was considered an acceptable price to pay. Paul’s innovation used in the Century, New Century and Reliance projectors was no longer necessary; his technology had been superseded.

5. Paul Camera, three-slot mechanism, c.1901. New arrangement of the interior gearing means that the exterior pulley wheel size has been significantly reduced, making the camera more convenient to set up and use. Paul’s 1901 catalogue (Cinémathèque française, CineRessources).

The new camera

Then there is the later (last?) version of Paul’s camera. He wrote (in 1936) that this also had the three-slot movement. In a projector, the purpose of this novel mechanism was to reduce screen flicker, and camera mechanism/shutter design does not affect flicker. Paul explained that in the camera, ‘owing to the special design of the movement, pictures may be taken in a dull light when it would be impossible to photograph with a camera of ordinary construction’.[6] There would also be changes to the filmed image: the narrower shutter blade and/or longer exposure of each frame would cause some motion blur, especially with subjects crossing the field of view, but that isn’t always detrimental. The example that Paul gifted to the Science Museum is, I believe, the only one known. He seems to have sold very few cameras; perhaps none but museum examples have survived.

6. PAUL’S NEW “RELIANCE” ANIMATOGRAPH. Display advertisement, cover of Optical Lantern and Cinematograph Journal Vol. 1 No. 8, June 1905 – ‘The Latest Triumph of Animated Photography. Improved Intermittent Movement … The outcome of ten years’ experience in manufacture and use’ (Stephen Herbert Collection). The advert was repeated in No. 9, July 1905. The Optical Lantern and Cinematograph Journal / Optical Lantern and Kinematograph Journal (1903-1907) became the Kinematograph and Lantern Weekly, and finally the Kine Weekly.
7. Reliance projector, c.1905, showing cross/pinwheel. From Hasluck’s Book of Photography (1905), also used in the OLCJ Vol. 1 No. 8 review (Stephen Herbert Collection).
8. For the Reliance, Paul maintained the three-slot mechanism/12-tooth-sprocket arrangement of the Century, but the slots were now no longer in a wheel, but reverted to the familiar star-cross form. One of the three curved edges of the three-arm cross can just be seen here, to the lower right of the large steel wheel that contains the activating pin. The casting includes the wording “RELIANCE / 1904 MODEL / ANIMATOGRAPH PATENT”. I cranked an example of this machine in the Feroze Sarosh collection, and it turned more easily than the Century (provenance, Gordon Trewinnard Collection; photo by Stephen Herbert).

The Reliance projector, the end of the line

Perhaps a hint that the Century projector could cause problems is in the name of this ‘improved’ successor. The Optical Lantern and Cinematograph Journal front-page display advertisement in June and July 1905 (Fig. 6), for Paul’s Reliance Animatograph (‘improved intermittent’) at ‘Reduced Prices’ suggests that perhaps this new design was not selling well. As we have seen, Paul’s ‘novel’ intermittent design was being superseded by other manufacturers’ multi-bladed shutter machines, which reduced screen flicker by this simpler method, requiring less precision in manufacture and operation. The rarity of Paul projectors that survive today might suggest that his machines did not have a big market share at this time. However, it’s important to realise that pre-1906 most projectors were sold in quite small numbers. Fairground showpeople certainly purchased machines early on, and shop-conversions opened up in many locations in the very early years of the century, but permanent purpose-built cinemas only started in 1906-07 when there was a boom in the industry.

It’s possible that the problems with the early models had damaged Paul’s reputation. In late 1904 he wrote about what we now call a ‘soak test’:

‘Every mechanism is tested by joining together the ends of a 3 feet length of film to form an endless band, which is run through many thousands of times without injury: intending purchasers should see this test made before deciding on a machine.’[7]

Had this been introduced in 1896, or at least been in force before the 1901 Century was brought to market, things could have been different. As it was, some earlier showpeople might not have been too pleased that their unknowing ‘beta testing’ with marketed machines had been at their expense, and had no doubt cost them lost shows and landed them with unreliable projectors.[8] To be fair, other manufacturers had also discovered that more rugged machines capable of taking the punishment of long running were necessary.

9. A surreal image from the race for flickerless projection. Advertisement for Nicholas Power’s projector, Supplement to the Kinematograph and Lantern Weekly, 30 January 1913 – ‘Flickerless’ and ‘Rock Steady’. Introduced c.1907, the particular American ‘Power’s’ machines that had a novel intermittent mechanism for fast pulldown allowed a smaller ‘cover blade’ on the shutter and therefore smaller ‘anti-flick’ blades. They were big sellers in Britain for many years, as evidenced by whole-page advertisements such as this one. Page from scrapbook (Stephen Herbert Collection).

For whatever reason, Paul was losing the market to a multitude of new equipment from many manufacturers in England, including projectors by the Walturdaw Company, W.C. Hughes & Co., the Warwick Trading Company, Leo Kamm, the Charles Urban Trading Company; and imports by Gaumont, Pathé, the Edison Manufacturing Company (London), and others. Furthermore, as R. B. Foster points out, ‘the use of an oil bath, suggested by Wrench in 1907, reduces friction’ and it would also have significantly reduced noise and protected the vulnerable mechanism from dirt and grit.[9] Within a short period the oil-bath would become an essential part of any professional Maltese cross projector. Foster wrote (in 1912, published 1915): ‘The popularity of the Maltese cross mechanism revived after the introduction of the oil bath.’ Paul knew that if he wanted to continue to compete in the film projector business, he would have to redesign and re-tool – yet another major expense, and involvement, in which he would have been reluctant to invest.

It seems that towards the end of his projector manufacturing, Paul might have abandoned his own mechanism designs and started using a ‘beater’ movement (i.e., the design used by much of the competition). A Century Animatographe with brass plate (No. 4) in the Lester Smith collection is fitted with the patented three-slot movement, but another example of a Paul Century Animatograph [without the final ‘e’] (No. 19) in the collection of Soterios Gardiakos is identical except that it has a beater movement, rather than the three-slot movement. Either the original movement caused problems for the user of this particular example and was replaced soon after purchase, or the beater was fitted to some later models at the factory.

10. The unexpected Bioscope/Paul ‘beater movement’ projector (Lemai Collection, Québec). Screenshot from a video on YouTube of an interview between Ian Christie and Jean Pierre Sirois Trahan, ‘Robert W. Paul, pionnier du cinéma en Grande-Bretagne.’

A unique hybrid

Recently, a projector with both Paul’s name and ‘Bioscope’ cast into the main body, but with a Bioscope-type ‘beater’ movement rather than a Paul mechanism, and a Henry Joy 1905 patent number, has also come to light in Québec (Joy was a design engineer who worked with Charles Urban). Ian Christie has written about this example on his blog and makes a perceptive and important point:

‘From what I could see […] there was no way of explaining this anomalous object. François Lemai may have been disappointed that he didn’t have a ‘genuine’ early Paul projector, but for me it was a true archaeological ‘find’. If we’re serious about material history and media archaeology, we should expect to discover objects we can’t immediately identify – things that ‘shouldn’t exist’.
Early film historians have been notoriously shy of talking about the actual engineering, or commerce, of their field (mainly because they lack the skills, if we’re honest). Here I was confronted by a machine I couldn’t classify, or date; and there must have been many such hybrids in the rough and tumble of cinema’s first decade. It was an unexpected, but welcome, case of what I’d come to Quebec to advocate.’[10]

Such an encounter would have flummoxed almost anyone, but Ian gives a good account of why this can’t be a Paul-design machine.

Guy Edmonds has suggested that the existence of this machine might indicate that by that late period Paul had abandoned his own-design projectors, and was selling a new machine that was actually an Urban Bioscope:

‘The Lemai Bioscope is indeed a wonderful example of history confronting us with paradoxical information. The weight of evidence which it presents leans very much in one direction. Looking at it as a Paul design, everything is wrong, looking at it as an Urban Bioscope, the only anomalies are the ‘R W Paul London’ cast-in name and the rather low serial number which does not fit in the progression of other known Warwick and Urban Bioscopes as the features evolved through the period 1898-1914. Its shutter too is ‘classic’ Urban Bioscope. It doesn’t have the slender single blade of Paul’s Reliance but a rather broader blade of 60 degrees or so. It presents here as single-bladed but that is because it is missing its violet tinted ‘anti-flicker’ blade. These fragile components made from early plastic have disappeared from the vast majority of all surviving Bioscopes. It would be wonderful to put together a working collection of these devices so that we could better judge the various merits of their designs as well as experiencing for ourselves what I call the ‘flickerscape’ of early cinema. Essentially then, the Lemai machine is a good example of the Model K Urban Bioscope which was produced towards the end of the first decade of the [20th] century. The most useful identifying feature is the Urban-Joy patent expansion chamber (designed to confine any film ignition solely to the frame in the gate). This does not appear in the 1907 Charles Urban Trading Co. catalogue but is present in the 1910 edition. I don’t think I know of any surviving Paul projectors dated after 1906. I would therefore hypothesise that the machine that is now in the Lemai collection was made by Urban at Paul’s request with his name on it. This would have enabled Paul to continue trading his ‘own’ wares while gradually ceasing production towards the end of the first decade, and pursuing other activities. Of course, I would welcome any further confounding evidence!’[11]

In the video about this machine (see Fig. 10 above) Ian Christie remarks, ‘It really is the beginning of our modernity… it’s very technologically sophisticated.’ I make a rather different interpretation. This Bioscope is essentially the 1894 Demenÿ design, predating successful film projection. And although a direct link with the very beginnings, I see it also as the start of the final chapter in the story of the essential development of analogue film apparatus; the beginning of the end of the machine age.

The Last Machine?

In 1980 Michael Chanan wrote:

‘It is inconceivable that cinematography could have been invented earlier, not only because it would not have attracted anyone’s attention as an opportunity for investment, but also because the technological means did not exist. The film apparatus depended on a degree of precision engineering which had simply not been attained fifty years earlier.’[12]

Chanan’s assertion that no one’s attention would have been attracted by the idea as an investment in earlier times is questionable, since it was a potential ‘magic show’ that would have engaged spectators and extracted their spare coppers at any time in the 19th century. A hundred years before cinematography, fantasmagore Étienne-Gaspard Robert (Robertson) had used auto-focus glass-slide projectors on rails, producing zooming phantoms onto screens and sheets of smoke, thrilling audiences. Also, the invention of cinematography might have been for domestic use; an option that some pioneers, including the Lumières with their Kinora viewer, developed as a potential alternative to public screenings. Michael Chanan makes some good points in exploring the development of ‘interchangeable parts’ during the 19th century, but mistakes this advance of the interchangeability required for mass production, for the different requirements of mechanical invention. The established facts counter Chanan’s assertion about ‘precision engineering’.

In fact, my own research strongly suggests that all of the ‘movements’ later used in conventional motion picture systems from the mid-1890s onwards were already in use in other industries. Even earlier, John Harrison would surely have been bemused at the suggestion that Urban’s Bioscopes or Paul’s Animatographs were somehow mechanically superior to his 18th-century clocks, decades in development, which used almost incomprehensibly fine precision mechanics and highly ingenious balances to help estimate a ship’s position on the globe and potentially prevent wrecks and save lives. And we must remember too the ‘writing boy’ automaton of Pierre Jaquet-Droz, and also his ‘organ-playing lady’; not grey ghosts on a screen, but mechanical beings ‘brought to life’, solid to the touch. Commercial production of motion picture mechanisms would have been less easy, though definitely possible, half a century earlier than it actually happened, and invention would have been entirely feasible – had the photographic provision also been available; and very soon it would be.

1. Left: Gearing of part of the Antikythera mechanism, made around 150-100BCE. X-ray courtesy of the X-Tech Group. Object ID 500004211 (Antikythera Mechanism Research Project). Right: Bioscope projector mechanism, early 20th Century, gears side. Serial No. 375 (Hove Museum).

And let us travel back further, two thousand years, to the Antikythera mechanism: a machine to predict eclipses, to peer into the future, defying the limitations of time’s flow. Like Hollis Frampton’s 1971 essay, which provided the name of Ian Christie’s 1994 book and television series The Last Machine, I see devices such as the Urban/Paul Bioscope projector (Lemai Collection), apparently a unique survivor, and also Paul’s own-design projectors not as a ‘technologically sophisticated’ herald but as the final important stage of development in the visual/optical strand of a mechanical age.[13]

As machines, those Animatographs and their Bioscope and Cinematographe cousins hardly exceeded or even approached previous technological marvels in their mechanical ingenuity or complexity, but were a late step on the road towards the eventual extinction of mechanical moving image machinery and materials. The star-cross film mechanism was literally the last stage in the analogue technical development that had brought fusion-effect moving images to the screen, via Beale’s Choreutoscope, and Anschütz’s Projection Electrotachyscope.[14] Dressed up and evolving slowly with a few iterational improvements, and later as hybrids with the addition of electronic sound, the old-school film machines existed alongside the development of electronic television scanning, video, and the early years of digital imaging. The classical mechanical technology that Paul’s film machines represented finally died as a mass medium with the obsolescence of 35mm cinema projectors and cameras, essentially a minor development of the same mechanisms from the 1890s that had lasted so well, as the 20th century gave way to the 21st – exactly a century after the appearance of Paul’s ‘advanced’ Reliance projector, his last innovative moving picture machine.

So although mechanical motion picture film technology had a full century of flourishing life after its arrival, it was indeed ‘The Last Machine’ and not ‘technologically sophisticated’ in any disruptive sense, not the First of a revolutionary family of devices (Frampton preferred the milestone of the ‘black box’ of radar, rather than the introduction of video) heralding a new visual-electronic age of modernity. Hero of Alexandria, whose automata impressed the ancient world, would have been amazed but perhaps not puzzled by the photographic aspects of the Bioscope-Animatograph systems which brought figures to life with the aid of a visible chemical method of capturing shadows, while he would have immediately grasped the mechanics, which were less complex than some of his own. But surely Hero would have been confounded by the transistor and its invisible molecular activity.[15]

The ? Cinema

Frampton wrote that film is part of the single ‘machine’ that forms The Last Machine of cinema. So perhaps it wasn’t just the mechanism that was required, but the flexible medium of celluloid? Not really; not specifically. Leo Kamm’s Kammatograph (patented 1899, marketed from 1900) could both take and project 45-second movies, comparable with the capability of the first Lumière machines, but using safe and manageable glass plates instead of flammable and awkward twisty filmstrips. Cinema would have been different in that alternate celluloid-free world, but it would still no doubt have happened and been exploited in some way. The sensitive photographic emulsion? Well, small-format ‘instantaneous’ photography dates from the late 1850s, so that was already achievable decades before cinematography.[16]

So, all the technology – including the photographic processes – and equivalent mechanisms for something like the Kammatograph existed by 1860, but the ideas, energy, and circumstances necessary to make something similarly effective evidently failed to coalesce. Perhaps after all there’s something in Michael Chanan’s belief that earlier, it would have ‘failed to attract investment’ – but it’s also important to remember that commerce is only one ‘driver’ for invention. Another is inquisitiveness. There was rarely financial reward in building giant telescopes, for example. Had a wealthy experimenter wanted to devise, for personal satisfaction and interest, a photographic motion picture machine with the potential for a one-minute movie, and hit a potentially successful route, suitable engineering mechanisms and techniques were known and available in 1860. They would perhaps have been striving for five or seven frames per second, and it would have taken some experiments to establish the real requirements. People were trying, certainly, but mostly at a bricolage stage and progress was slow, and it did take the development of paper film and then celluloid as a potential medium to speed things up. Or were there other reasons? But certainly, for invention, the precision engineering was there long before it was required. Just because something can happen, it doesn’t necessarily follow that the ducks will line up in a row.

In answer to the hypothetical question ‘Was there some special technological magic in the achievement of cinematography, or the development of cinema that would follow?’ some would answer: It showed us the world on our local screens, while giving us a new medium with striking artistic and political potential, enabling Murnau’s Sunrise, Hitchcock’s Vertigo, and Akerman’s Jeanne Dielman 23 quai du Commerce 1080 Bruxelles, but mostly it was just Carry On Up The Khyber. The ‘humble’ clock, more sophisticated technically than a basic Bioscope or Animatograph mechanism, altered the nature of work, controlling us by splitting our lives into mechanical segments that could be counted and managed. Engineering developments such as steamships and railways and aeroplanes and automobiles actually changed the world – in some cases tragically, as they poisoned it and disrupted indigenous species and peoples – and literally took us around the globe. For those who stayed at home less glamorous engineering marvels such as sewers and generators and diggers altered our lives in major, arguably mostly positive ways. And in terms of communication, the telephone revolutionised personal and professional contact while the telegraph aided the development of capitalism and other isms that changed the very nature of society. Meanwhile cinema kept us glued to the screen, literally mesmerised, as what was left of the flicker that Robert Paul tried to suppress engaged our neurobiology at least as much as the movies’ content; we drifted away in consumer dreamland as our precious lives ticked by.[17]

12. Projector stand pivot, projector patent drawing and photograph. Described in the patent: ‘I also provide means by which the inclination of the apparatus may be varied so as to obtain the best effects on any given screen. For this purpose the base A […] is provided with a cup-shaped seat u […] resting on a hemispherical surface u1, and is secured by the bolts.’ The ingenious arrangement was also used on Paul’s cameras, and echoes the Unipivot that was central to many of his scientific instruments. British Patent No. 4,686 of 1896 (Theatrograph, Science Museum Collection, photo by Stephen Herbert).

Innovative features, and an enigmatic survivor

If the above review of Paul’s apparatus appears to be comprehensive, that’s misleading. A full account has still to be researched and written.[18] Apart from the actual ‘movement’ and shutter arrangements, many features and improvements were introduced over the years. Some were very simple but ingenious, such as a universal pivot arrangement on the base of the iconic Theatrograph with cast-iron stand (Fig. 12), which allows the projector head to be adjusted minutely and simply in any horizontal tilt direction. Others deserve at least a mention: the improved film gate, manual safety shutter (dowser), more resilient materials; and an arrangement for re-framing the screen image if ‘out of rack’ with parts of the picture rising above or dropping below the screen. This ‘optical framing’ was innovative, and became a standard feature of film projectors. The few surviving cameras need to be carefully examined to ensure that they have revealed all their secrets. A detailed illustrated inventory of existing R.W. Paul film equipment would be invaluable in aiding our understanding and evaluation of the development of the machines.

13. A unique survivor? A seven-arm cross mechanism in the Projected Picture Trust Collection (Ian Christie, A Robert Paul Newsletter, January 2004). Photo by the Projected Picture Trust.

One mystery for instance: the Projected Picture Trust (whose logo is the iconic Paul Theatrograph) has an incomplete mechanism in its collection that appears to be a very early Paul design. This was illustrated in Ian Christie’s January 2004 Robert Paul Newsletter. Is the attribution an assumption because of the distinctive seven-arm star cross movement? It would seem to be a design dating from before Paul’s adoption of the double cross (for the first commercial models), yet differs significantly in layout from the familiar illustration of the earliest known projector. Is this a relic of an experiment from the very earliest days? Or perhaps a machine by an unknown competitor, using Paul’s movement design? Such ‘copies’ are known to have once existed.[19]

False trails and mistakes

In his later reminiscences, Paul was generally candid about his false trails and mistakes. He ‘admitted’ years later that despite working on the camera, ‘strangely’ he did not at first realise that an intermittent would also be necessary for projection.[20] He also acknowledged that he didn’t anticipate that having only an intermittent sprocket on his projector, and no continuous top sprocket, would cause problems with the film feed, resulting in jerky movement of the film strip as it came off the spool.[21] After introducing a top sprocket to cure this, he still didn’t immediately fit a lower continuous sprocket, essential for smooth ‘take up’ of the film.

He also admitted that he failed to take into account, when designing his projector with two interlocked intermittent sprockets, that this would cause problems with shrunk or badly perforated film, and he had to revert back to one intermittent sprocket.[22] His three-slot mechanism, that was an ingenious method of reducing flicker, could be challenging to operate and the early model was subject to problems caused by the different method of locking the sprocket during the ‘dwell’ period. In the 1930s he reflected, perhaps somewhat forlornly, that these ‘flickerless’ designs never took off, and subsequent projectors in the industry had a four-arm design; which he had used in his 1897 Fireproof Animatograph but abandoned for the three-slot ‘improvement’.

14. Enigmatic mechanism on the Experimental Department workbench. R.W. Paul 1901 Catalogue (Cinémathèque française).

Another mystery

There is another mystery machine that’s perhaps worth mentioning, even though it is unlikely to still exist. In his catalogue for 1901 Paul shows the workbench in his Experimental Department. We can see a machine that is either a camera mechanism, or a projector head. The obvious key point is the apparently oversize format of the film, judging by the rollers and picture gate. It seems to take a film that would be at least the width of Biograph’s 68mm. At about that time, 1900, the Lumières built a camera for wide film. I don’t know of any record of Paul making such a machine. It’s just possible that the mechanism is from another manufacturer, as Paul advertised repairs of machines of all makes. However, from the very limited information that can be gleaned from the exposed gearing etc, I would say that it does have a Paul ‘look’ about it, the large gear resembling that used on two models of Paul projectors. So it isn’t only the majority of the films that have disappeared; this tantalising glimpse is all that we have of a most intriguing machine.

15. OLCJ December 1904, Vol. 1 No. 2. Front cover half-page display advertisement for the Robt. W. Paul HIGH POWER Electric ILLUMINANT, Nernst-Paul Projection Lamp. ‘Nine times the candle power of the usual Nernst lamp. Illustrated catalogue (No. 131) of Apparatus for Projection, Post free on request’ (Stephen Herbert Collection). The Nernst-Paul lamp was described by British Patent No. 12,546 of 1905.

The Nernst-Paul lamp

Let us next take a brief look at the unusual light source that Paul developed, the Nernst-Paul lamp. The original Nernst Lamp was a clever electric illuminant design intended for many applications. Developed by the German physicist and chemist Walter Nernst in 1897 at the University of Göttingen, these lamps were about twice as efficient as carbon filament lamps and they emitted a more ‘natural’ light (more similar in spectrum to daylight). They had been promoted at the Universal Exposition in Paris in 1900.[23] It seems that Robert Paul was able to increase its power significantly, and his version, marketed as the Nernst-Paul lamp, appeared in about 1904. Resembling a conventional incandescent lamp in a special holder, the unique feature of the unit was that it was started by heating the bulbs with a small open-flame spirit burner, to warm up the filaments. Despite fairly heavy promotion by Paul in the first few years of manufacture, and claims of good sales, the Nernst-Paul lamp was never to become a popular choice with lanternists or film projector users, and few surviving examples are known.[24] This was perhaps Paul’s final innovative item intended, at least in part, for film use. With a maximum screen width capability of 10-12 feet they would have fallen from favour after about 1906 as cinema screens sometimes exceeded that size, and the previous electric illuminant, carbon arc lamps, continued to be widely used for cinema film projection in Britain until the 1970s.[25]

Towards an assessment

In order to evaluate Paul’s position as a mechanical design engineer we would need to know what was being striven for with each development, how successfully the goal was achieved, and any drawbacks that emerged. How advanced / advantageous / novel were his developments? We would need to place Paul’s inventions and developments into context with engineering progress in the film industry as a whole. We have some of this data, but much is missing. Gathering such information, making sense of it through the ambiguity of explanatory language and terminology, physically using the devices to experience the actual rather than theoretical results, and writing it all up, would be a significant task. Working on such a research project while avoiding a subjective teleological mindset would be difficult too. As a consequence, full evaluation of Paul as a mechanical design engineer is not yet possible. What I can tell you is that, in my opinion based on a working examination of several existing examples, his projector mechanisms were manufactured to a very high standard. Any problems were not due to shoddy machining or assembly or cheap materials. In that sense, his engineering was first class. If there is criticism that can be made concerning Paul and his early mechanical film equipment it is that on more than one occasion he went to market too early, before the bugs were ironed out, but of course there was considerable pressure to do so.

It’s clear that by 1909 Robert Paul had too many film-making competitors. His equipment was also fighting in a very competitive market. His improved Nernst lamp had not prospered as a film projection illuminant, his camera capable of filming in low-light situations doesn’t seem to have been wanted, and his novel projectors (three-slot intermittent) were no longer necessary, as the technology had advanced with alternative designs. He no longer had any advantage.[26]

Comments and corrections are encouraged.
Stephen Herbert, January 2021

If you find The Optilogue useful, and haven’t already done so, why not Subscribe here to get email notification of every new post?

Next time: After the film business, and ‘Who made the films?’

Notes and references

Acknowledgments will appear in the final part of this multi-part blog post, together with a full bibliography. This article has not had a full fact check, so if you intend to use the references cited you should first go back to original sources to confirm them.

  1. A Century mechanism from the Lester Smith Collection is illustrated in Barnes (1997) Vol. 5. An impromptu video by Stephen Herbert and Lester Smith, ‘Robert W. Paul 3-slot mechanism 35mm film projector 1900’ can be found on YouTube (accessed 20 September 2020). The Reliance projector was reviewed in the June 1905 Optical Lantern and Cinematograph Journal [OLCJ] Vol. 1 No. 8, from a description given to the reviewer by Paul’s manager, Mr J.W. Smith. [return to text]
  2. A variation on the star-cross. Essentially a three-arm mechanism, but in fact the ‘arms’ had been dispensed with in this version, the slots being made in a disc, and the locking of the sprocket as each image was being projected being achieved by a sprung knob catching in one of the slots. The three-slot disc would turn the sprocket one-third with each slot. Since that one-third turn needed to move the sprocket 4 teeth (one frame of film), the sprocket needed to have 12 teeth; perhaps unique in film projector design. [return to text]
  3. It would also have increased the general brilliance of the screen image, as noted by the OLCJ reviewer (OLCJ, Vol. 1 No. 8, p. 178). However, with every ‘improvement’ of this kind, there is usually a negative aspect. Increasing brightness makes flicker more perceptible. This can only be fully evaluated by experiment. [return to text]
  4. The sprung arm that engages a knob in the slot to lock the sprocket with each ‘dwell’, used instead of the common curved cross-piece sitting against the curve of the cam, soon created problems through wear, which is most likely why Paul reverted to a cross shape with the subsequent Reliance. The small-circumference sprocket – used in both Century and Reliance models – is also a negative factor, as the moving teeth engage with fewer film perforations, therefore creating more stress on each perforation (as pointed out by Robert A. Mitchell, ‘Heart of the Projector Mechanism’ Part 3, International Projectionist Vol. 27 No. 9, September 1952). [return to text]
  5. Paul’s cylindrical or ‘drum’ shutter of 1896 had two curved obscuration sections (equivalent to ‘blades’), but was geared to give one opening per frame, so effectively was about the same as a conventional single-blade flat shutter. There are some advantages in this design over a flat-bladed shutter, but flicker is not affected if geared to give one-opening-per-frame. From 1902 various inventors came up with a multi-blade shutter to reduce flicker. From about 1907 the new intermittent design of the Cameragraph projector, introduced by Nicholas Power’s company in America and imported into many countries including Britain, was also a factor. Power’s intermittent reduced the pulldown period without creating undue stress on the film. [return to text]
  6. The quote is from Paul’s 1901 catalogue. A fast pulldown arrangement in a camera can be hugely advantageous. In my own experience, shooting Super 8 in the 1970s became possible indoors, without special lighting, for the first time with the introduction of the Kodak XL camera range, which had a fast-pulldown mechanism with smaller ‘shutter blade’ as well as a very wide aperture lens. [return to text]
  7. Paul, Supplementary List of improved apparatus for Optical Projection. Season 1904/5. [return to text]
  8. It is of course possible and perhaps likely that Paul made some recompense to the early purchasers who suffered problems, but this would not have assuaged their disappointment. [return to text]
  9. R.B. Foster, Hopwood’s Living Pictures (1915), p. 128. A Maltese cross enclosed in an oil bath had apparently been employed in the Optigraph projector in the U.S.A. before 1900. [return to text]
  10. Paul’s Animatograph Works blog: 25 May 2019, ‘A genuine fake?’, and 21 November 2020, ‘Confronting a Challenge’. [return to text]
  11. Email from Guy Edmonds to Stephen Herbert, 17 December 2020. [return to text]
  12. Michael Chanan. The Dream that Kicks: The Prehistory and Early Years of Cinema in Britain (Routledge & Kegan Paul, 1980; revised 2nd edition, Routledge, 1996), 1980 edition p. 53., 1996 p. 52. Although I am critical here of some of Chanan’s assertions concerning technology, his book (1996 edition) is full of perceptive comment and also an indicator of the many avenues of research that can be undertaken to provide extensive and important context to early cinema studies. [return to text]
  13. Hollis Frampton, ‘For a metahistory of film: commonplace notes and hypotheses’ Artforum Vol. 10 No. 1, 1971. Ian Christie’s book The Last Machine: Early Cinema and the Birth of the Modern World (BBC, 1994) is still an important primer and companion to early cinema. [return to text]
  14. The star-cross was not the only mechanism that enabled film cinematography. Georges Demenÿ, C. Francis Jenkins and Charles Urban used the beater movement, the Lumières devised the pinframe, and others the similar claw mechanism. This is not an exhaustive list. But for cinema projection, the cross – in one form or another – reigned until the end of analogue motion picture presentation. [return to text]
  15. Hero, who was fascinated by catoptrica (studies of light reflection) and formulated the principle of the shortest path of light, would have been delighted by the dioptrics of the Animatograph’s lenses. [return to text]
  16. Lenses, especially for photographic projection, would improve over the years, e.g. the Petzval developments, but would have given an acceptable result in 1850. Powerful limelight illuminants were available from the 1830s, and electric arcs first appeared c.1850. [return to text]
  17. For a Marxist view of the controlling nature of the commercial screen industry, see Chanan (1980, and revised edition 1996). For an example of the conflict of politically motivated young filmmakers and their enjoyment of mainstream screen entertainment, see (for example) Stephen Herbert, ‘The Young Ones: Virginia Handley’, Making Better Movies, February 1986. At a 1972 film screening session I asked Gordon Gow, film reviewer, how he could bear sitting through a particularly self-indulgent feature film that seemed to go nowhere, and which I had just projected for him. ‘It doesn’t matter what’s on the screen,’ he told me, ‘so long as the projector lamp is on and it’s running. It’s the flicker, the beat. If you hadn’t laced the film in the projector I would still have been there, watching.’ Nevertheless he was sufficiently aware of the film’s content to write, with his usual rare insight, the review for Films and Filming or wherever. [return to text]
  18. I do not have access to Paul’s patent for 1900, one of the years engraved on the Century projector plaques (was it an uncompleted application?) so my account might need to be revised at some point. The 1900 application is titled ‘Projecting Photographs,’ so might have been related to the slide projection facility of the Century projector. Also, I’m a technician not a design engineer, and sixty years after first encountering the Maltese cross design I’m still struggling to understand some of the mechanical nuances. I’m undertaking further study; I think it’s what they call Lifelong Learning.
    British Patents applied for by Robert Paul after 1897 include:
    486 of 1899, ‘Taking and Projecting Pictures’
    487 of 1899, ‘Gearings’
    11,997 of 1899, ‘Animated Photography’
    14,372 of 1900, ‘Projecting Photographs’
    26,747 of 1901, ‘Taking and Projecting Animated Photographs’
    I am not yet certain which of these were Completed and Granted. A complete list of Paul’s Patent Applications and Completed Patents has not yet been compiled. Many thanks to Deac Rossell and the late Richard Brown for the information given here. [return to text]
  19. The slots in the cross have a rounded end, but the slots in all known surviving Paul projectors have a square end. Only the illustration of the ‘first’ machine shows slots with rounded ends. So I would say that either it is a very early Paul design, the earliest known example to survive, or it’s a machine by someone else, using Paul’s basic concept. [return to text]
  20. Or perhaps this ‘admission’ was a way of explaining away the apparent contradiction of his claim that ‘soon after’ the initial use of the original Acres-designed camera early in 1895, he (Paul) designed and made a star-cross mechanism camera, with which he claimed that ‘most of the films made in 1895’ were shot. It does seem difficult to accept that if Paul had designed and made such a camera in early-mid 1895 he wouldn’t have been fully aware of the requirement for intermittent movement in a projector, when he wanted to build one. If his ‘admission’ is true, then it calls into question the extent of his early grasp of the technical aspects of the subject. [return to text]
  21. Other pioneer film inventors also had to discover this the hard way. [return to text]
  22. R.W. Paul, ‘Before 1910: Kinematograph Experiences’, Proceedings of the British Kinematograph Society No. 38 (BKS, 1936). [return to text]
  23. ‘The Nernst lamp was an early form of incandescent lamp. Nernst lamps did not use a glowing tungsten filament. Instead, they used a ceramic rod that was heated to incandescence. Because the rod (unlike tungsten wire) would not further oxidize when exposed to air, there was no need to enclose it within a vacuum or noble gas environment; the burners in Nernst lamps could operate exposed to the air and were only enclosed in glass to isolate the hot incandescent emitter from its environment. The lamps were quite successfully marketed for a time, although they eventually lost out to the more-efficient tungsten filament Incandescent light bulb.’ (Wikipedia, accessed 10 December 2019). Nernst lamps were used in one of the first practical long-distance photoelectric facsimile (fax) systems, designed by professor Arthur Korn in 1902. [return to text]
  24. The lamp is described in detail in Paul’s Supplementary List of Improved Apparatus for Optical Projection. Season 1904/5. The Science Museum collection has a ‘3-element electric, projector lamp by Nernst-Paul. Object No. 1971-61’. The attached brass plate reads ‘NERNST-PAUL / ELECTRIC PROJECTOR LAMP. ROBT. W. PAUL …’ etc. The same collection also includes a slide projection lantern of the Nernst-Paul type, Object No. 1905-150. The History of Science Museum, Oxford, has in its collection a ‘Nernst Filament Projector Lamp, by R.W. Paul, London, c.1900-25. Inventory Number: 90793’. An inventory of all known surviving R.W. Paul film-related equipment in museums and private collections would be a useful project. [return to text]
  25. For an accessible, well illustrated historical review of lighting sources for image projection, see Patrice Guérin, Du Soleil au Xenon: des techniques d’éclairage a travers deux siècles de projection (Prodiex, 1995). [return to text]
  26. To go further would be a separate specialist research project. Some information can be gleaned from the pages of the Optical Lantern and Cinematograph / Kinematograph Journal, 1904-06, and photographic trade periodicals. [return to text]

4 thoughts on “Robert W. Paul – Films and Technology: Part Seven. That annoying flicker, a new camera, and The Last Machine?

  1. Well done Steven, well explained but I cannot take it all in in one go, I will savour it over the week.

    What’s next?



  2. Hi Lester, well – the final two installments include a consideration of Walter Booth’s role in the film making, some comments about the ‘directing’ of early cinema films, thoughts about ‘the real Robert Paul’ and his position as an instrument maker, and the link with Faraday’s optical experiments. Then we’ll be leaving RWP for pastures new, but I hope to return for a one-off roundup post – probably in April. Many thanks for supporting The Optilogue with material and encouragement.


  3. Hi Stephen,
    Very interesting account, with good explanations. I find it fascinating that RWP included no less than 3 ideas for intermittents in a single patent (fig.2)! He seems to have been so busy with inventing film devices in those years that you wonder how he found time to produce films and run an instrument business.
    Perhaps one should also add panning heads to his other important film inventions? (1897?)
    Maybe you can deal further with the above-mentioned Powers projectors in a future post? They became quite dominant and yet I haven’t seen much historical discussion of the various models, or how they worked.
    If you will be discussing Booth in another post as you say above, I noticed an interesting blog about him (the best film history is in blogs these days!) at the


  4. Re: Multiple variations of intermittents in one patent – yes, he was ‘covering bases’ there – but did actually need at least two of them as it turned out. I’d like to know more about the development of the Powers machines – there is a fair bit of information out there, and the later models are common enough in Britain to get to play with one. I did set one up at MOMI many years ago, for a public show. A Cameragraph (not a great name for a projector) turned up in a local junk shop here a couple of years ago, but at a very silly price. However, although I’ve included a lot of technical description in these Robert Paul posts, it’s been laced with some other subjects and I’m not sure how many pix of sprockets and gears the average Optilogue reader will take. Maybe some time down the line. Re [Paul]: “….you wonder how he found time to produce films and run an instrument business.” Well, yes. More on that very soon.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Create your website with
Get started
%d bloggers like this: