Cave Research Group publication 14
1961 Oxford University Expedition to Northern Spain
|1961 Expedition Report (CRG 14)
The expedition was fortunate in being able to give extensive cover to many subjects. Of the twelve expedition members five were keen photographers, possessing between them three twin-lens reflex cameras, three 35 mm. cameras and one folding 120 roll-film camera. Much to our disappointment we were unable to obtain a 16 mm. cine camera. We took 2000 still pictures, nearly half of which were in colour, and obtained a full record of the journey, daily routine and surroundings of the expedition. The survey work underground was recorded together with features of interest in the caves themselves such as rock and calcite formations. Above ground the subjects consisted of erosion patterns in the limestone rock and the illustration of the various experimental techniques such as water tracing and geophysical measurements.
For cave photography twin-lens reflex cameras, giving twelve exposures 2 1/4 inches square on 120 film probably provide the best answer. The negatives obtained are of a reasonably large size, the camera is comparatively compact and is simple to operate. Film changing is easy and is not required too frequently. A metal ever-ready case is manufactured to fit most Rollei cameras, which will protect them against knocks, dirt and water. We used one of these with great success.
We also used a Rolleicord masked to take twenty-four exposures of 35 mm. size on 120 film. This had the advantages that it could be protected by the Rollei metal case, only one camera was needed for colour and monochrome work and larger size transparencies could be produced if desired. The masking down from 2 1/4 inches square gives a telephoto effect; in general this makes little difference but can be a disadvantage when a large chamber is to be photographed.
Film is very much a matter of personal choice; it is best to use the film with which you are most familiar. We used Ilford FP3, HP3 and HPS monochrome emulsions, the bulk of the work being done with HP3. For colour we used Kodak High Speed Ektacbrome 35 mm. and Ektachrome 120. The extra speed of the 35 mm. material was found especially useful underground. Since 1961 a number of new films have been introduced and High Speed Ektachrome is available as 120 roll film. The choice is almost embarrassing. For caving it is best if films are carried in tropical packing, as this is added protection against damp. In this connection both Ilford and Kodak publish useful leaflets giving hints on photography in the tropics and on travel abroad, including processing, care of film, customs etc. They also produce data sheets on all their sensitive materials showing development times, sensitometric curves, colour sensitivity, filter factors and speed.
The main lighting equipment consisted of a Rollei-flash and extension head with four ten foot lengths of extension cable. In this we used PF1 flash bulbs, clear for monochrome and blue for colour. In addition we had several small flash units and one which could take PF60 flash bulbs which have an Edison screw fitting. These latter bulbs provided sufficient light to illuminate large chambers or pitches. Although flash bulbs contain a coloured spot to indicate whether they are in good condition we found it very difficult to tell when underground whether the spot had changed in colour. For this reason a number of exposures were spoilt because faulty bulbs failed to fire properly. Approximately 3% of the bulbs used failed in this way. This is much higher than the expected failure rate and must be attributed to the combination of damp atmosphere and the physical shocks of transport underground. To alleviate this as much as possible the bulbs were packed in a waterproof screw-topped tin, which was carried in a satchel or ammunition box together with the other accessories wrapped in polythene bags and a towel. The towel was used to wipe mud from our hands before handling equipment. We also wore thick polythene gloves to keep our hands as clean as possible. These were a great comfort when climbing over the very sharp rocks found in Pozo Palomeru, but could make the hands rather clammy.
The original intention was to develop all monochrome films whilst we were in Spain. There were several reasons for this; the best possible results are obtained if negatives are developed immediately after they have been exposed, exposure problems in caves are such that a check on the results obtained is desirable so that if necessary shots may be repeated, and any undiscerned malfunction of equipment is immediately apparent. To balance against this are the disadvantages of the extra equipment and chemicals which must be carried and the quite large proportion of time involved. As things turned out we were only able to process about 25% of our films on the expedition; it is remarkable how easy it is to break photographic thermometers, especially when they are not kept solely for photographic use. The first was dropped down the entrance pitch of Pozo Palomeru and the second was left for too long in the sun.
On any expedition which is not too restricted on the amount of equipment which can be taken our experience indicates that the best compromise would be to develop the first 15% - 20% of the films exposed, followed by occasional developments to keep a check on the condition of the equipment. The development of the first 25% of our exposures was sufficient to give us confidence that we could judge exposure correctly, and also to show up a camera with a pinhole in the bellows and a malfunctioning shutter. The films developed on return to England were not noticeably inferior in quality to the rest, showing that the quality factor is not important on expeditions.
In retrospect the expedition appears to have been a success photographically. A very limited selection of our photographs is used to illustrate this publication. None of our colour slides is represented here but as far as possible we tried to record subjects both in colour and in monochrome. In some cases this was not adhered to, thus few pictures of our journey are in colour and some of the surface geophysical work is only recorded in colour. Personally I would have preferred to have done more work in colour but this is probably because I was rather daunted by the thought of four hundred negatives most of which would have had to be printed.
. M. Austin, Shenfield, Essex, April 1964.