Unitol Developer: Gone But Not Forgotten

All sorts of things turn up in boxes of old photographic equipment. Over the past year I have been buying daylight-loading developing tanks for my other blog/website which is intended to be a resource centre for present-day users of these tanks as well as a source of information on their history.

http://rondinax.wordpress.com

In an Essex 35 tank that arrived I found a cardboard calculator for Unitol developer. Unitol was made by the Johnsons of Hendon Ltd. It was introduced in late 1950. The BJ Alamanac included Unitol in its 1951 edition:

The essential new feature of "Unitol" is that, unlike most fine-grain developers, it may be diluted within wide limits so that it becomes possible to use it with the utmost economy – and simplicity – by following the slogan "One ounce; one film; use once; then discard". It is reckoned that one ounce of the concentrated solution is necessary for the proper development of one film, and that it is by then exhausted for practical purposes…Quite apart from this convenience, however, "Unitol" is a fine-grain developer of the highest grade…A most convenient calculator and film group chart has been prepared for use with "Unitol". Sold at the nominal price of 4d, it enables the time of development for any dilution, at any temperature, of any film to be immediately calculated by the rotation of a disc.

"Unitol" was extremely popular, at least in UK. I am pretty certain that the main active developing agent was Meritol. All the clues (sold in liquid form, not compatible with Johnsons 142 retarder, half-a-stop loss) suggest Meritol, and, as far as I am aware, the formula of the commercial mix has never been published. Meritol was Johnsons own patented agent. Another clue is that the Johnson advertisement in the same edition of the BJ Alamanac states, After long research Johnsons are now able to present a concentrated liquid fine grain developer. Meritol itself was patented in 1937 (applications made in 1936). Two patents (GB466625 and GB466626) cover the chemical synthesis and the formulation of a developer (essentially Johnson's Superfine Grain). Meritol was invented by Frank Clement Starnes, who worked for Johnsons. Starnes had died in 1945, aged 62, and I wonder whether his death, together with getting the company running properly after the war, was responsible for that statement, After long research.

Meritol was formed from paraphenylenediamine and pyrocatchin (pyrocatechol, catechol), each a developing agent. The additive product is a new compound with different properties from each of its constituents. Claims that the two components can be used instead of Meritol are not, therefore, accurate. Research on Meritol continued. I even found a paper in a chemical journal from 1989 that shows the distinct structure of Meritol.

Finding the Unitol Calculator (which would now of course be launched as an app) was a reminder of that 1950s mantra: Ilford Film; Kodak Paper; Johnsons Developer. It has to be said though that D76/ID11 caused wavering with the last part.

Johnsons of Hendon advertisement in BJPA 1951

The Unitol Calculator:

Centre was pushed out to form the
central disc of the calculator

Finally, the headings of the Starnes patents that covered Meritol:

Minolta Autocord. Second Impressions

I put a roll of FP4+ film through the Autocord last week to see how it handled compared with the Rolleicord (and Rolleiflex since it has a lever wind).

First though I replaced the piece of felt on the inside of the door and a circle of leatherette that was missing from the upper spool holder. Milly’s Cameras (order from the eBay site) supplied the materials very quickly indeed. Compared to the Rollei, the back fitting to achieve light tightness is pretty crude.

Arrow shows the replacement felt

I didn’t find the handling so convenient as the Rolleicord. Focusing involves moving one hand (and sometimes two) under the lens board in order to move the lever from side to side. I really found the lack of a concentric depth-of-field scale a hassle. Situated around the lever drive with tiny knobs to move an inner wheel, I gave up on it and used my iPhone depth-of-field app instead. I also found that the position of the shutter did not feel quite right.

Depth of Field Scale

In using a TLR I usually use the magnifier and hold it at eye level with my forehead resting on the hood rather than low down like a box camera. But as I did so the magnifier moved out of the way and so I had to keep my eye a distance from the magnifier. This doesn’t happen to me with the Rolleicord or with any Rolleiflex I have owned.

Magnifier in viewing position

I do like the solid metal lens cap and, once I got used to it, the way it attaches to the bayonet fitting of the viewing lens.

In terms of handling the Rolleicord wins easily. However, when it came to the results, the lens on the Autocord did live up to its reputation. I found it the equal of the Tessar in terms of sharpness. It seemed to have more contrast than the Tessar but I would really need to do a side-by-side comparison to be sure.

This Autocord has certainly lasted well; the mechanisms seem robust and the lens looks and behaves as good as new. I will give it another try soon with infra-red film. I wonder for what wavelength the infra-red focus point was set.

Rondinax, Rondix, Essex, Kent: New Blog and Resource Site for Daylight-Loading Developing Tanks

I have just launched a new blog/website on daylight-loading developing tanks. It includes links to videos which show how easy it is to use these tanks for developing 120 and 35 mm film, downloads of instruction manuals, tips on buying and something of their history. It is still a work in progress and more material is being added.

For those wanting to develop films without a darkroom as well as experienced users, I hope readers of this blog will enjoy the new one.

It is at:

http://rondinax.wordpress.com

Magazine Bias to Canon and Adobe?

In successive weeks, Amateur Photographer has been accused of favouring Canon over Nikon and Adobe Photoshop (the full fat version) over other editing software. The former was stoutly denied by the editor but I am surprised to see the letter now. A couple of years ago there was a clear bias towards Canon, subtly and not so subtly, in AP – to the point at which several family, friends and former colleagues (all very satisfied Nikon owners) would e-mail 'did you see that in AP' stories to laugh about.

The writer of the letter stated quite rightly that Canon for a short time held the lead in DSLR technology in terms of the performance of the sensors fitted. A number of professionals swapped to Canon at that time. Canon marketing was also clever. The distinctive colour of their long lenses shows what sports photographers are using and the generally sheep-like amateur camera buyers did what sheep do – they followed. Two high-profile professional wildlife photographers I know are provided with top of the range telephotos on long-term loan. Their cameras and lenses are noticed and copied. The distinctive colour helps again of course. Since then, of course, Nikon have come back with a vengeance in the DSLR stakes.

The obvious bias towards Canon in UK photographic magazines shifted most noticeably after the Olympics. The photographs of Usain Bolt with that Nikon must have been worth a fortune in marketing terms. Interestingly, the photographers who infest Wimbledon were sporting a greater proportion of black-and-gold lenses last year (an interesting diversion from the tennis and on the same level as looking for the binocular brands on BBC's Springwatch).

Both Canon and Nikon obviously make (or assemble) excellent cameras and the competition between them has generated rapid progress over the past 10 years.

The writer on Photoshop made the point that there are other software suppliers while Mac Aperture users (the premium end of the computer market) do not even get considered. We all know that the professional graphics package is the full version of Photoshop but that it comes at a very high price with a new selling strategy that stinks. Software specific articles in magazines are a pain because non-users are paying for content that is often completely irrelevant. If I were the editor, I would advocate a problem-based approach and then deal in outline the steps that would be needed in a variety of software packages. Generic advice on such controls as levels, curves etc that are common to lots of packages would also be useful.

Even though some of the more obvious bias in AP has gone, I must support the two letter writers. Some of the recommendations and comments have been outrageous over the years, not just by AP but by many magazines. Even when pictorial and graphic evidence was presented to the contrary and there for all to see, one brand was favoured in comparison articles.

Digiscope or Superzoom Bridge Camera for Birding?

A correspondent who sells secondhand optical equipment for birding on eBay tells me that the prices of digiscoping adapters for major brand telescopes are falling. He thinks the rise of the Superzoom ‘Bridge’ cameras I have discussed in this blog is the reason. The extra focal length gained by using a scope (see my Post of 19 August 2012) is now of marginal advantage when we can get the 35 mm equivalent of 1200 mm focal length from a superzoom. Add the large number of pixels captured and the fact that there is image stabilisation in the superzoom, then I can see why the digiscoping may become a thing of the past fairly quickly.

It is obviously much quicker to point a superzoom camera at a bird than it is to mount the scope on a tripod, aim and focus the scope, attach the camera by whatever attachment you have and then press the shutter.

Another correspondent says he has just had a rare bird accepted from a photograph at 1000 mm equivalent with his Nikon P510 handheld.

Over the next few weeks I will eventually get round to comparing my two systems (Nikon P50 Superzoom vs Leica Televid and Panasonic Lumix on adapter) side by side at the mouth of the river and in the garden.

Minolta Autocord versus Rolleicord Vb. First Impressions

For current users of 120 film, the Minolta Autocord has an almost cult following that rivals that of the Rolleiflex and Rolleicord. The lens is argued to be the equal of and sometimes better than the Zeiss Tessar in the latter cameras.

Having read the stories, I was keen to compare the two cameras. It is, of course, not fair to compare the performance of two cameras, both 50 years old, picked at random from those on sale. Conditions of storage, amount of wear and servicing could all be different and affect the original design and construction differently. Unfair, yes, but I will do it anyway.

I bought the Autocord from a UK seller on eBay. As soon as it arrived I realised it was in excellent condition and identified it as the RG 3rd version of 1963. That same day, I checked the shutter speeds electronically and found they were consistently about ½ stop slow and not worth applying a correction when using films like FP4+.

Please bear in mind that the Minolta Autocord was very different in price from the Rolleicord. In Amateur Photographer of 15 February 1961 I found one advertisement for the Autocord at £53-9-6d. In another advertisement on 14 February 1962, the Autocord was £50-7-10. Rolleicords at that time were about £85.

Please also bear in mind that Japanese cameras were very slow to gain acceptance in Britain in the late 1950s and early 1960s. They were regarded as cheap, unreliable and inferior imitations of German products. The trade was still locked into the British agents of German manufacturers. As one camera shop owner said to me in the late 1950s while looking down his nose at a Japanese TLR, ‘I have to sell these because of the price but I hate having to do so. Real photographers will always use German cameras.’ I do not recall ever seeing an Autocord in a camera shop; Yashica, especially the 4x4 yes, Minolta no.

So, without having used it yet, these are my first impressions.

The Autocord is heavier than the Rolleicord Vb (930 vs 1000 g). In general, the construction of the Autocord is crude compared with the Rolleicord. For example: screw heads are on show (anathema to premier German manufacturers); the opening mechanism is very crude and closure of the back relies on felt seals in places. The hood is non-removable and the sports finder release mechanism somewhat unreliable.

In terms of focusing, I prefer the side wheel of the Rolleicord to the front lever of the Autocord. I also prefer the split-image centre of the Rolleicord screen to the plain ground glass centre of the Autocord. I can see no difference in brightness.

The depth-of-field scale is around the focusing knob of the Rolleicord which makes it easier to use than the one on the Autocord. In the latter it is around the winding crank and the focused distance has to be read off the front scale and then applied to the depth-of-field scale. The Autocord but not the Rolleicord has an infra-red focusing mark.

Setting the shutter speed and aperture I find easier on the Autocord. I hated the exposure value system when it was introduced and I hate it now. Having to unlock a lever to change shutter speed and aperture was, and is, infuriating.

A major difference between the two cameras is the winding crank of the Autocord, thus making it comparable with a Rolleiflex like the T model.  For the type of photography I do with TLR cameras, I actually prefer the winding knob of the Rolleicord but I can see that, in its day, a rapid wind lever would have been an attraction.

The next job is to load a film and try the Autocord in action.

Exakta Varex Cameras. 3: 2013 Perspective

It was nostalgic fun to have an Exakta (well three, actually) at the eye for a while again after an interlude of nearly 40 years. I bought three bodies which came with a total of five lenses from different eBay sellers.

It is very unfair to extend performance of an old camera to criticism of the manufacturer because so much depends on how it has been treated by its owner or succession of owners. So many cameras of the 1950s and 60s have been handed down to children who then abandoned them in attics, garages and sheds until moving house.

There were five problems with one or more of the bodies.

In all three (one Varex IIb and one IIa) the foam rubber that cushions the mirror had crumbled away or was in the final stages of doing so. That was easily replaced by material supplied by an eBay seller.

Replacement foam above the mirror

In both IIbs but not the IIa the frame counter was not working. It jumped all over the place when the film was advanced. This mechanical failure I am told is a common problem.

The frame counter did not work in the two Varex IIbs

The mirror was beyond use in the IIa. The silvering had deteriorated badly, starting it seems, from chemical reaction as the foam rubber broke up. The mirrors in the IIb were fine with just a little deterioration at the edges near the foam.

The mirror of a Varex IIa showing deterioration of the silvering

The major problem in the IIa but not the IIbs was the state of the shutter curtains. The deterioration of the material is a well-known problem. The curtains were wrinkled and had, when a light was held behind them, what seemed like pin holes. However, pin holes are usually a seller’s description. This is far a more serious condition. The whole (rubber?) material within the curtain is in process of breaking down and the light leaks are extensive, as the following photographs show.

Wrinkled shutter curtain - tell-tale sign of light leakage

Light coming through the shutter curtain

Light coming through the shutter curtain (LED torch in mirror box)

Smooth curtains not leaking light in a Varex IIb

Temporary (paint the curtain) and permanent (do-it-yourself curtain replacement or professional repair) solutions are shown in a number of websites. However, professional repair is an expensive route (£200 plus + VAT, I was quoted) which is why so many Exakta bodies are lying ‘beyond economic repair’.

I also tested the shutters of the two IIbs, both electronically, and with film. I did not test the IIa in view of the light leakage through the curtains.


One of the shutters tapered at 1/500th and 1/1000th sec so could not be used at those speeds without servicing. That shutter sounded better than the one in the second body which fired with a squawk that is said to indicate a lack of oil. The second was fine to use at all speeds. In terms of accuracy, the pattern was the same or similar to that reported in various websites. The higher speeds were slow: the slower speeds were fast.

Taking the IIb with the good shutter, from 1/500 to 1/60 sec (I could not get readings at 1/1000 with my set-up) there was 1 stop overexposure (to the nearest whole stop). From 1/30 to ½ sec timing was within ⅓ stop. At 1 sec there was 1 stop underexposure (i.e. the mean exposure of five firings was 0.54 sec instead of 1 sec).

In the body of the one of the IIb that tapered at high speeds, the variation was somewhat different. I held the sensor in a fixed central position in the film frame so that I was not looking at variation across the frame. 1/250 sec was near enough1/250 sec (mean 1/290). 1/60 and 1/30 sec were slow by one stop. ¼ and ⅛ were pretty well spot on while ½ and 1 sec were within 1/3rd stop of being accurate.

By knowing the accuracy of he shutter I was able to make appropriate corrections when I came to testing the lenses and actually using the better IIb to take a few photographs.

Rumour has it that the mechanical build quality of the IIa was better than the IIb. I cannot comment. All these cameras were in need of servicing. I doubt if any had been serviced since they were manufactured.

All the 50 mm lenses (two f/2.8 Tessars and two f/2 Pancolars) had problems. The pin that engages with the lever on the body had been torn out of one of the Tessars. I can only guess that somebody had inherited the camera and had then tried to change the lenses using brute force. The notched lever on the body was also bent (replacement found on a dead Exa). That lens was a write off and soon on its way to the recycling centre for glass and metal.

The other Tessar had slightly stiff focusing and some cloudiness on an inner element (what is the that cloudiness in chemical terms?) so contrast was low. In use it could still produce a reasonable image in high contrast conditions of bright sunlight.

One of the Pancolar was of the earlier design (without the automatic depth of field indicator lugs)(see 11 June post). Again it was slightly cloudy internally (again - what is that cloudiness?). It gave soft, low contrast results on film. The other Pancolar was of the later design with automatic depth of field indicators. Edge fungus was present but only affecting f/2 aperture. It was slightly cloudy internally and again produced soft, low contrast negatives.

In short the 50 mm lenses were way past their best. The Pancolar had the reputation of being fairly low contrast when new but my original 1960s Pancolar was capable of giving very sharp, punchy transparencies with Kodachrome.

Included with one of the outfits I bought was a 135 mm f/4 Sonnar. I was very impressed with the quality (so is its new owner). No sign of any cloudiness or fungus with just a few specks of something internally. The results on film were excellent - very sharp and excellent contrast. That lens had lasted well.

135 mm f/4 Zeiss Jena Sonnar

This Exakta lens hood fits all the 50 mm and the 135 mm f/4 lenses

Original Ihagee filters are not that common

The cameras did the job I wanted them for (to produce developed 35 mm for another project I will describe later) and have now gone to new owners.

So, after handling and using Exakta cameras again, would I like to turn the clock back and return to 35 mm film photography from full-frame digital? NO. NO. NO. We really have never had it so good. 35 film is in the past and offers no advantages over what we have now other than, for black-and-white, a stored silver image.