Saturday, 31 December 2016

Photographic Objects

"A forward-thinking young man"
For my last post of the year, I wanted to reflect on some work that I exhibited during 2016; I have only very rarely exhibited photography (other than online) but this year I made a number of 'photographic objects' for exhibitions to which I was invited to contribute. As these were all created with chemical photography, the work falls under the remit of this blog.

Invited to contribute to the exhibition Art:Science:Life by Dr Lucy Lyons at the Ipswich Art School Gallery, the brief was to respond to an object in the adjacent Ipswich Museum's collection, and make a piece of work which could take the original object's place in the museum, while the object itself would be displayed in the art gallery next door, along with the information about the artwork, under the banner of 'Curated Responses', alongside a number of other invited artists.

Curated Responses
I chose the two aircraft recognition sheets from the Ipswich at War gallery in the museum. These were printed on some form of translucent material, which provided the initial inspiration to form my response. A number of years ago, I had read H.G. Wells' novel The War In The Air and was struck by its prescient qualities. My first thoughts were to use this, the book itself, as an object to make a painting, but on reflection, a much more apposite approach was to echo the material qualities of the objects I had chosen. To this end, I used Kodak High-Resolution Aerial Duplicating film to make contact prints of the cover and colophon of my paperback of the novel: not only did the film have a similar look to the aircraft recognition sheets, it was also manufactured to duplicate aerial reconnaissance photographs. Asked to write a statement for the 'Curated Responses' room, I provided the following:
H.G. Wells' novel The War In The Air was first serialised in 1908. Written before Louis Bleriot's successful cross-channel flight, it imagines a war in the near future in which flying machines are decisive; the use of aircraft in the two World Wars, renders aspects of Wells' speculative future prophetic. Taking the cover and the title page (with the reverse showing the original publication date) from a paperback edition of Wells’ book, I made contact prints on Kodak High Resolution Aerial Duplicating film. This high contrast film is designed to make positive and negative duplicates from high resolution aerial photographic negatives; its transparent qualities mimic the aircraft recognition sheets from the Second World War that Wells would live to see.

"A forward-thinking young man"
I called the piece "A forward-thinking young man" from a quote in the book about the protagonist that could equally be applied to Wells himself.

At the Doomed Gallery in Dalston, for the London Pinhole Festival in April to coincide with Worldwide Pinhole Photography Day 2016, I showed a small set of pinhole images, shot two years earlier, presented as positives on glass, appropriate as the original negatives were made with glass plates.

“Talking about pinhole photography with security guards in the park”

I titled the piece, “Talking about pinhole photography with security guards in the park” to relate it directly to my experiences of taking the photographs, rather than what they might show. The work was accompanied by a statement which read:

Related to an ongoing series of photographs using previously unexposed vintage photographic glass plates, for 'Worldwide Pinhole Photography Day' in 2014, I shot a number of photographs using homemade pinhole cameras around the London 2012 Olympic Park. The photographic plates used in the pinhole cameras were Ilford Special Lantern plates, designed to make glass slides for projection, coated in 1965. These were developed as negatives and then contact printed on Ilford N.50 Thin Film Half Tone plates (from 1957) to create positive transparencies on glass for display. The title is a reference to the photographer’s aberrant behaviour and its being outside the sphere of reference of those in authority.

For the positives, created simply by contact printing the original pinhole glass negatives, I used orthochromatic plates so I could work under red lights and develop by inspection. As the physical qualities of the plates themselves seemed important, especially their fragility, I wanted to display these in such a way as to allow the viewer to inspect the plates closely. I could have shown the positives on a light box, but I felt like this would have diminished some of those qualities that I wished to emphasise, so I constructed a shelf which would hold the glass plates upright, projected a short distance from the gallery wall. The lighting was not entirely sympathetic, but this did have the effect of making the viewer look at the plates all the more attentively in order to comprehend the images.
Prototype for a Photographic Object
I returned to using the Kodak High Resolution Aerial Duplicating film for an exhibition called Machine Flight at the Pictorem Gallery in November. Close to the gallery in Walthamstow, there was the ideal source material in locations on Walthamstow Marshes. I took an initial set of photographs on 'Expired Film Day' of the railway arches where A. V. Roe built and then flew the first British aeroplane on the marshes in 1909; I shot the photographs on 4x5 film with a lens that could have been used at the time, a Rapid Rectilinear. I returned to take a second set of photographs of an adjacent feature on the marshes, known as 'bomb crater pond', less than a couple of hundred metres from the railway arches. This pond was created by the impact of a V2 towards the end of the Second World War. It seemed too appropriate a coincidence that within a generation from the first heavier-than-air powered flight, the space age was born, and that this would come together on an otherwise unremarkable patch of north London.

I shot the photographs on FP4 and Plus-X from the 1970s, and contact printed these negatives on a continuous strip of the High Resolution Aerial film, eighteen images, the whole length of positive film being around 2.5 metres long in total. Given how this aerial film would have been originally used, I made a device a little reminiscent of a microfilm reader, allowing the viewer to scroll through the images sequentially, forwards and backwards; I titled this a prototype, as its Heath Robinson construction would ideally have been improved.

Thursday, 22 December 2016

127 Day December 2016

Two weeks ago, for December's 127 Day, I shot three rolls of Ilford FP4 Plus cut down to the 127 format, using my Baby Ikonta. I chose FP4 Plus to coincide with the 'shoot week' of December's #FP4 Party. Taking the same route as three (and four) years ago, I cycled around the boundaries of the London 2012 Olympic Park, shooting some of the same views. I developed all three films with RO9 One Shot at 1+50; the results, although generally good, demonstrate some of the limitations of the camera's Novar lens, notably in the vignetting seen across all the photographs.

Saturday, 17 December 2016

Kodak Plus-X

Kodak/Eastman Plus-X in 16mm, 35mm, medium format and large format sheet film
Eastman Plus-X was first introduced as a motion picture film in 1938, and shortly afterwards produced for still cameras in a number of different formats as Kodak Plus-X. The emulsion number for Plus-X as a motion picture film was -231, with Kodak's standard prefix codes of 7 for 16mm, and 5 for 35mm. As a motion picture film, Plus-X was available in both negative and 16mm reversal stock. For still camera film, Kodak Plus-X had the code PX for many years (with PXP for medium format 'professional' films; PXE for Estar-based 70mm film; and PXT for thick-based sheet film), but it was reformulated around a decade ago, and was then designated 125PX. A comparison of development times shows these to be broadly similar, but changed in many cases by 15-30 seconds in many developers. Kodak's technial data sheet for the new version states:
"To reflect our enduring commitment to black-and-white photography, black-and-white film production will take place in an even more advanced film-coating facility. New technology applied to these superior, time-tested emulsions will result in slightly different processing times for the film family. But the same great films—those you've known and trusted for years—will still deliver the same breathtaking results."
One notable difference between the two versions was the new Plus-X was provided with development times for a three-stop push to EI 1000, while the earlier film was only recommended to be pushed no more than two stops; both films' data sheets stated that a one-stop push to 250 could be achieved without a change to development times. In my own tests below, I did not attempt more than one-stop push, given that I was working with discontinued film, although the 35mm motion picture film was manufactured in 2010, not old enough to really be concerned with increasing exposure to compensate for a loss of sensitivity with age; in some other formats, the Plus-X film I shot was much older.

In the Kodak Reference Handbook from 1946 it is described under 'General Properties' for Roll Film and Film packs as being:
"High speed, fine grain, excellent gradation, wide exposure latitude. The speed and balanced color sensitivity make this film particularly suited to a wide range of outdoor conditions. It also has ample speed for well-lighted indoor subjects. The low graininess and high resolving power permit high quality enlargements many times the size of the original negative."
While for 35-mm and Bantam (828) films:
"High speed and fine grain. For general miniature camera work this film should be used unless light conditions are very adverse or unless a very high degree of enlargement is intended."
Plus-X was originally rated 50 ASA, but at some point in the 1950s this was increased to 80 ASA (this thread gives some information on Plus-X ratings). When speed ratings were changed for black and white films in 1960, Plus-X was rated at 160 ASA for a time, before gaining its 125 ISO rating, which it retained for nearly fifty years (Kodak's reference hand book implies the presence of the one-stop safety factor in the statement about Plus-X that, "When it is desired to reduce the exposure to a minimum, these values can be doubled with little danger of serious underexposure..." ). Additionally, the motion picture stock was recommended to be shot at a slower speed, 80 ISO in daylight and 50 under tungsten, which may just reflect the process of striking a positive from motion picture negative film, rather than a slower emulsion.

Eastman Plus-X was discontinued in 2010, with the notice for the still camera version announced the following year - although the production runs may have both stopped at the same time if the emulsion itself was the same. Incidentally, the Massive Dev Chart still has Plus-X on its main chart, not on its discontinued/unlisted page. Kodak's rationalising of the film stocks it produces in recent years has meant the discontinuation of many of its classic films. This does leave Kodak without a medium-speed traditional emulsion film (Ilford's FP4 Plus being the closest equivalent still available). Kodak suggests TMax 100 as a replacement for Plus-X; this film uses a modern T-grain emulsion. For most of the period that Kodak was manufacturing Plus-X, it also produced Verichrome Pan, another still picture film with a traditional cubic emulsion at the same speed as Plus-X, only discontinued in 2002; Verichrome Pan does appear to have been available in some formats (126, 127) that Plus-X was not, but both were available in the most common formats - 35mm, medium format and sheet film.

Minolta 16QT with 16mm Kodak Plus-X, develop before date Sept 1971
MPP pinhole with 4x5 Kodak Plus-X, develop before date July 1972
I had first used Plus-X in a ready-loaded Minolta-16 cartridge with a "develop before" date of September 1971. Around the same time, I also acquired a box of large format Plus-X from 1972 in a job lot, which I used for both this year's 'Expired Film Day' and on Worldwide Pinhole Photography Day, which I rated at 25 to compensate for the loss of the film's sensitivity over the more than four decades since it was made. Apart from this loss of sensitivity, the quality of neither film appears to have been much compromised with age. Unintentionally, I had begun to use Plus-X after it had been discontinued almost by accident; I subsequently bought a 100-foot roll of 16mm film for 110 cartridge reloads and other subminiature formats, after using up two rolls of Kodak WL Surveillance film, and finding the Photo Instrumentation film rather grainy. As Plus-X had been a motion picture stock, I wanted to use it for a separate project that I have been pursuing, looking at film locations; given how recently it has been discontinued, I found it relatively easy to find across Plus-X in 35mm and 120 online.

35mm Kodak Plus-X motion picture film latitude test
To test the film in 35mm, I bought some bulk motion picture Eastman Plus-X 5231. According to Kodak's guide, the date of manufacture for the 35mm Plus-X that I bought is 2010, which would mean that it was in the very last batches made before discontinuation that year, based on the edge code once developed. I tested the latitude of the film, as shown in the contact sheet above. For the first row, the film was exposed at indexes of 40, 80, 100, 125, 160, and 200. However, with the light changing due to quick-moving thin clouds, shooting manually, I couldn't be sure that I had a perfect set of exposures, so I repeated the latitude test a couple of days later. For the second row I used the same set of exposure indices, but the lighting on the day was more consistent. The film was shot with a Canon A-1 SLR and developed in Ilfotec LC29 at a dilution of 1+19 for 6 minutes at 20ºC. Both tests showed good latitude with a moderate amount of contrast over the fairly short range of exposures, and a relatively clear base, presumably being good for motion picture use, as well as possibly useful when scanning. Part of the reason for choosing these speeds was an attempt to be precise over whether any adjustments for age needed to be made, given that the motion picture stock is recommended to be shot at a slower speed (80 ISO in daylight) than the still camera version (125 ISO), which may just reflect the process of striking a positive from motion picture negative film.

Canon A-1 with Plus-X rated 40
Canon A-1 with Plus-X rated 200
Although I used a narrower range for the test than for other films I've tested, the results appeared to show the Plus-X has fairly good latitude; the two examples above from either end of the scale of exposures I used are both quite acceptable, in the lower image it might have been possible to pull more detail from the shadow areas. Other than the Plus-X from the 1970s, the last batches of 35mm motion picture stock and the medium format from the past decade were either shot at box speed, or generally rated at 100 rather than 125. I haven't tested Plus-X for push processing apart from one roll at 200, pushing one stop (or 2/3 of a stop) in Ilfotec DD-X. With the lighting conditions when the film was shot, the results were fairly high in contrast, I also shot the film with a yellow filter, which helped provide detail in the sky. As Plus-X has only been discontinued within the last decade, there's still a lot of the film around in different formats, although since I bought my last bulk roll, I have seen that prices have increased online. Perhaps Kodak Plus-X isn't significantly different from Ilford's FP4 Plus to make shooting it today anything other than a historical curiosity - I had never used the film before it was discontinued - although as a motion picture stock, it's a fortunate curiosity, appropriate enough to the ongoing project shooting film locations.

Mamiya-16 Automatic with 16mm Eastman Plus-X
Pentax Auto 110 with 16mm Eastman Plus-X
Agat 18K (35mm half frame) with Kodak Plus-X motion picture film, developed in Ilfotec LC29
Kodak Retina IIa (35mm) with Kodak Plus-X motion picture film, developed in Ilfotec LC29
Kodak Retina IIa (35mm) with Kodak Plus-X, rated 200, push processed in Ilfotec DD-X
Kiev-4 rangefinder (35mm) with Kodak Plus-X motion picture film, developed in Ilfotec LC29
Ikoflex Ic (medium format 6x6) with Plus-X, develop before date of 03/2006, developed in RO9 One Shot
Zodel Baldalux (medium format 6x9) with Plus-X, develop before date 02/2007, developed in Ilfotec DD-X

Sources/further reading:
Kodak's history of motion picture film stocks
Plus-X Pan (PXP) tech sheet on
Plus X (PX125) tech sheet on
Kodak Reference Handbook 1946

Tuesday, 29 November 2016

Found Film 3

In a recent purchase of a bundle of mostly uninteresting 35mm compact cameras, two of them had part-used rolls of film inside. The cameras were a Polaroid PZ2001 and an Olympus Trip AF.  The films were both Kodak Gold consumer colour negative films, and possibly could have been in both cameras for a number of years, the Trip AF being older, but there was nothing to securely date the films in either. This generation of plastic point and shoot film cameras probably lost value quicker than any other type of camera with the rapid and subsequent replacement of their place in the market by digital, and apart from the odd exceptional model of their kind, these are largely quite forgettable.

Polaroid PZ2001
Both films were stand developed in Ilfotec LC29 1+100 for one hour for monochrome negatives, rather than have them developed as colour: there might be nothing on either film, but stand development uses a minimal amount of chemistry. The Polaroid yielded the most results, although almost all were out of focus, and many over-exposed. As the Polaroid film hadn't been used up, I did shoot a couple of frames with the camera myself (below) - and got better results than everything else on the film in terms of focus and exposure.

Of the photographs already shot on the roll, most looked liked a holiday somewhere in America, with a Seaworld-type of attraction, what looks like festively decorated holiday apartments - or possibly a church and the decorations are for a wedding, and somewhere in the mountains (this last series of photographs being very overexposed - I imagine that the camera did not possess small enough aperture settings or fast enough shutter speeds to cope with using a fast film in very bright sunlight, but I have attempted to pull all of the detail out of the scans that was there). There are also two close up shots, both out of focus, of a flower and a lizard.

From the Olympus Trip AF there were just three frames that had anything remotely worth scanning - and perhaps not even that - all very underexposed, possibly needing the built in flash which didn't fire. These looked like they were taken in a junk shop, judging from the first photograph, while the other two look like accidental exposures. Given the few shots on the Trip, it feels less precious, but clearly the owner of the Polaroid camera went somewhere special and shot nearly a whole roll of film, before never finishing the roll, never developing it, leading one the speculate as to what the circumstances were that meant they never saw the results; however, this might just be reflective of how photographs were taken by many people before digital: once back from holiday, with the film not quite finished, those last frames weren't to be wasted, and the camera was put away in a drawer to wait for the next special occasion,

Monday, 14 November 2016

Zeiss Ikon Cocarette 519/15

Zeiss Ikon Cocarette 519/15
Many months ago, I shot a handful of test rolls with the Zeiss Ikon Cocarette, but then put this to one side as a consequence of initial results which were disappointing. Earlier this year, after acquiring a No.2A Brownie in a job lot of cameras, my interest was reawakened: both cameras use the obsolete 116 rollfilm format and I wanted to shoot with both on 11/6 this year for a '116 Day'; following this, last week I used the Cocarette again on 6th November as another calendrical 116 Day. When I'd made my first tests with the camera, I had begun to write up my experiences, of which it now seems like an opportune time to revisit, revise and post.

Zeiss Ikon Cocarette 519/15
Having some years ago written a post about the Icarette L, before writing about the Cocarette, I also wanted to pass comment about the popularity of camera names ending in "-ette" during the first half of the 20th century. Nettel's Piccolette was the first example I could find; both the Icarette and Cocarette were later but contemporaneous to each other and a little research has also thrown up the Gewirette, Makinette, the Pearlette, a Japanese copy of Piccolette, itself inspiring copies called the Dianette and Pionette, and the Nifcarette and Rollette. With the Piccolette and other 127 format vest-pocket cameras, the "-ette" suggests a small, compact camera, which my Cocarette certainly is not, being 20cm tall - partly due to being the 116 version. Like the Icarette with Ica, the Cocarette name was given to a new prestige line of folding cameras produced when Contessa-Nettel was formed by a merger in 1919, it came in a number of formats, and, also like the Icarette, this camera was continued by Zeiss Ikon once Contessa-Nettel had been combined into the new company, although it was discontinued earlier, around 1930 (the Cocarette does not appear in Zeiss Ikon's 1931 catalogue).

Carl Zeiss Jena Tessar lens in Compur shutter
My example ot the Cocarette dates from after the formation of Zeiss Ikon, and is badged as such around the lens, on the folding bed, and imprinted on the leather at the top of the body; the name Cocarette likewise appears in three places, while the model number does not, but possibly this may have been on the handle, missing on my camera (it does, however, still have the folding stand on the drop bed's front that appears to be missing on most extant examples of the Cocarette). Provided with a reputed 64 combinations of lens and shutter variants, my camera has the top-of-the-range Carl Zeiss Jena Tessar f4.5 120mm lens and Compur rim-set shutter. Both lens and shutter serial numbers can be dated to 1929, being relatively late in the production run. The focal length of the lens is a giveaway for the film type that the Cocarette uses: had the lens been 105mm, this would denote 6x9 on 120 film; that the lens is 120mm indicates that the Cocarette takes a 6.5x11cm frame size on 116 film - although not true for all cameras, this is a very good indication. Zeiss Ikon were systematic in assigning catalogue numbers to all their cameras (all Zeiss Ikon products in fact), although many cameras in certain markets were also referred to by a letter suffix to indicate different specifications; my Cocarette is a 519/15: the first number denotes the camera model, the second number the film format and frame size. All Zeiss camera models /15 would therefore shoot 6.5x11cm frames on 116 film.

Zeiss Ikon Cocarette opened for loading
The Cocarette has an unusual system for loading film: the top or side, depending on which way the camera is held, has a sliding latch, which when unlocked allows the user to remove a frame into which film is loaded (this is described as the camera's 'film race' in this US advertisement). There are two hinged flaps which hold the film spools either side, and the film needs to be threaded between inner and outer rails; this design appears to have been developed from Contessa-Nettel's earlier Piccolette, which was an improvement on the drop-in loading of the Vest Pocket Kodak that inspired it. It also appears that this design was promoted to reassure customers used to glass plates about film flatness - this advert describes it as entirely eliminating "buckling of the film".

Apart from the 'film race', the Cocarette functions as a fairly typical folder of its day. The camera is non-self-erecting: the lens is pulled out to the infinty stop of the folding bed's rails by hand. Frame advance is by red window and backing number, focus by estimation using a lever with markings for infinity, 30, 15, 10 and 6 feet (indicating this as an export model for US/UK markets); the focus lever does advance the lens further forward than 6 feet, but without distance markings, possibly as the margin for error when focussing may have been felt to be too great beyond this point. The rim-set Compur shutter has the full range of speeds from 1 second to 1/250th, as well as T and B settings; the f4.5 Tessar lens stops down to f32. For framing there is a brilliant finder with spirit level that rotates through 90º for horizontal shots and a wire frame finder: to use this, on the body is a small peep-sight that can be raised into position from a circular door on the back of the camera. This allows access to the lens for cleaning and removal (a feature that the Vest Pocket Kodak also possesses); either completely raised or lowered, this sight locks the rear door, but in an intermediate position the door can be rotated to remove it. Additonally, the lens is also provided with rise and fall in the vertical position.

Zeiss Ikon Cocarette in horizontal format with wire frame finder and sight raised
My approach to converting the Cocarette to use 120 film was to do this in a non-destructive way, such that the camera could potentially use 70mm film in future - or, as on the Summer 116 Day, I used some original, expired 116 Kodacolor film. Research online shows two aspects to this conversion - firstly, some method of securing 120 spools into the slightly larger gap for the taller 116 spools - which needs to include the ability to wind on the advance key, and secondly, masking the frame itself down to the width of 120 film. With access to laser cutting facilities at the time I bought the Cocarette, I had adaptors made that would fit the top and bottom ends of spools from acrylic. Initially I thought that this would be enough, but when attempting to load camera with 120 backing paper as a test, there was too much of a curl to the paper at both top and bottom - as the 11cm wide frame doesn't hold the smaller format taut across it. Perhaps in a more conventional folding camera, this could be used without masking, although cupping of the film would potentiallt affect the focus on the film plane. I made a mask simply by cutting runners from thin black plastic sheet, which I taped to the top and bottom of the frame, but the camera also needed another pair of small runners inside the slots themselves to ensure that 120 film runs straight down the middle of the 'film race'.

Zeiss Ikon Cocarette conversion - runners taped in place
I didn't make any changes to the viewfinder of my camera. Some examples of 116 conversion show the wire frame finders adapted to take into account the narrower frame. However, as using the wire frame finder - or brilliant finder for that matter - isn't exactly precise for the frame edges, and with 120 film only a small fraction is lost from the top and bottom of this image, I felt this to be unnecessary.

To test the frame spacing, I ran a roll of 120 backing paper through the Cocarette. The numbers which align with the red window are those for 6x4.5 exposures. As this exposure size isn't neatly divisible with the 11cm-long 116 frame, I counted turns of the wind on key to determine how far to advance the film between exposures. My first calculations were that I would need to make the first exposure starting with the number 2 on the backing paper to provide enough film to cover the frame; I estimated that 2 and 1/3 turns of the winding on key for each subsequent exposure was sufficient. To make this easy, there are three screws around the winding key to mark its position when turning. For the first test roll I simply discounted the problem of the circumference of the take up spool increasing as more film and backing paper is wound on. The first two images on the roll overlapped, but I then found an increasing distance between the frames. When I developed the first test roll, as well as the uneven spacing, this was marred by obvious light leaks (I discounted this being from the red window, as this should be light tight anyway - even with modern emulsions, the film's backing paper should be perfectly impervious, despite some comments that occasionally crop up in discussions online). Looking at the light leaks' position relative to the camera, it was clearly caused by a missing screw on the side which removes for loading. As I couldn't find a screw of the right dimensions to replace it, I simply used black tape to cover the hole from the inside.

Second test roll, Fomapan 400, first frame showing tape mark at start of film
For a second test roll, I took the first two shots with a gap of 2 and 2/3 turns, then 2 1/3, finally just 2 turns between the exposures. This showed I'd solved the light leak, but, although none of the frames overlapped, the spacing was too generous, which resulted in five shots from the roll of film rather than a possible six. The first frame was also right on the very beginning of the film, overlapping the tape, as in the image above. It seemed safer to begin with the number 3 aligned in the red window, instead of 2, given that this initial length of film might vary between manufacturers.

Rather than counting turns of the winding key, I decided for the frame spacing, I would try using the numbers on the backing paper. Had I only wanted just five shots, it would have been easy to use the numbers 3, 6, 9, 12, 15, but there's clearly enough film on a roll of 120 to get six exposures. Running backing paper through the camera again, I noted down where I thought each frame should fall, using the marks that precede the frame numbers as well as the numbers themselves. For a third test, using the red window, I aligned the first mark before the number 3, then 5, first mark before number 8, third mark before 10, first mark before 13, 15. However, this isn't necessarily always possible, as different manufacturers have different backing paper designs: Foma, and some other films have three marks before the frame number; Ilford films have four circular marks increasing in size before the frame number; unhelpfully, Kodak just has the word 'Kodak' and the film name before the frame number. When using the camera, I taped a note with these estimations written down so as not to forget where I was in the sequence when shooting; I have yet to try taking 120 film and taping it to the 116 backing paper that I now have from shooting the expired film earlier in the year, which could be an alternative approach.

Zeiss Ikon Cocarette focus lever
From my earlier tests, and using the camera during the summer, I realised that the focus scale was not accurate, and attempting to find out exactly why, I removed the panel at the back of the camera and using a loupe with some tape across the focal plane (I used some 120 backing paper with a hole in for the tape to best place this on the focal plane itself), it was clear that, when set to infinity on the scale, the lens was not extended far enough; at the 30ft mark, infinity seemed to be achieved. I then made the assumption, which I didn't measure, that I could simply shift each focus mark to the next nearest, so if 30ft is really infinity, then 15ft becomes 30ft, and so on. This worked well enough for the shots I'd taken on the last 116 Day, although a more permanent solution might be better, but the only practical way to do this would be to remove the infinity stop, which takes the form of a small peg screw, drill a small hole in the folding bed slightly forward of its original position, and replace it there.

As I wrote on my post for the summer's 116 Day, using 120 film in a 116 camera does make for an attractively proportioned image, especially suited to landscape photography, and, like the Zeiss Ikon Cocarette (despite my camera's focus issues which may yet require more attention), there are many of these cameras still around which can be used with currently available film with a little extra work.

Zeiss Ikon Cocarette with expired Kodacolor film
Zeiss Ikon Cocarette with Agfa Superpan 200
Zeiss Ikon Cocarette with Fomapan 400
Zeiss Ikon Cocarette with Ilford HP5 Plus
Sources/further reading:
The Cocarette series on Camera-Wiki
Cocarette models on Early Photography