From Stone-Age to microchip: the Geological Survey Drawing Office
|From: Wilson, H.E. Down to earth - one hundred and fifty years of the British Geological Survey. Edinburgh:Scottish Academic Press, 1985.|
|The text is derived from an 'orphan' work. BGS are committed to respecting the intellectual property rights of others. After extensive effort we are unable to trace the copyright holder of this work. Despite this, we would like to make this very important work on the history of BGS, written by a former member of staff of the Survey, available for researchers. If you are a rights holder and are concerned that you have found this work for which you have not granted permission please contact us with proof you are the rights holder.|
VIII From Stone-Age to microchip:the Geological Survey Drawing Office
For the first hundred and thirty years of its existence virtually the only output from the Survey was the series of geological maps and, occasional, memoirs which had started with De la Beche's first eight 'coloured' sheets in 1832.
These maps, known always by their 'Sheer-numbers and names, usually that of the town nearest the centre of the map, were based on the new series Ordnance Survey one-inch to one mile series — 359 sheets in England and Wales, 205 in Ireland, each covering an area of 216 square miles and measuring 18 inches by 12 inches. In Scotland there were 131 sheets, each 24 inches by 18 inches and covering the Country in blocks of 432 square miles. Though the Ordnance Survey Sheet coverage of the country has long since changed, the geological maps, now on the scale of 1:50 000, still cover the same areas as the original survey.
The production of these maps, from the earliest days, has involved the skills of engravers and draughtsmen and for most of the detail of this chapter we are indebted to Eric Tallis, whose career,starting as a draughtsman with the Survey and ending as 'Superintendent of Maps', encompassed the great technological revolution of the mid-twentieth century.
It is doubtful if there was a drawing office as such in the early years of the Survey. In that age of the 'gifted amateur' many of the Victorian botanists and zoologists were accomplished artists and produced technically excellent drawings. It is probable that the early geologists were also their own draughtsmen and colourists, producing a manuscript geological map on the printed Ordnance Survey base map.
It is not clear when the Survey employed its first draughtsman, but there was a drawing office in Jermyn Street in the eighteen-seventies under Ramsay's Directorship, producing compilations from the geologists' clean copies'. These were subsequently engraved by the Ordnance Survey staff in the Map Room at the Tower of London and later in the old Cavalry Barracks at London Road, Southampton. All this work was done on paper, either using direct tracing or reduction using proportional dividers. The inaccuracies resulting were compounded by the water colouring — paper shrinks along the grain of fibres when wetted, and the best colourists used a soaked map, bedded on sodden newsprint, to get even colours, though often at the expense of gross distortion.
'Stone Age' in the chapter title is perhaps a misnomer as lithography was used more for detailed drawings, inked in on prepared stone slabs, than for maps. Chalco-graphic would be a better term, as the nineteenth century was the age of the copper plate. The early maps would have been engraved directly onto soft, flat copper plates by an engraver working from a completed fair drawing or 'dry proof' produced by the field geologist or an assistant. These engravings were, of course, mirror images of the original and the engraver's skills included the ability to produce a 'negative' image.
The maps were printed by the intaglio process, a slow and time-consuming method which gradually eroded the engraved plate. A good early copper plate 'pull' has an embossed ridge at the edges due to the great pressure involved, while the ink can be felt as a raised image on the surface of the paper.
The printed maps were hand-coloured, using water colours made by Newmans of Soho, which were produced as rectangular blocks about 2 x 1 x ½ cm, specially made to the Survey's specification and embossed with the name of the geological formation — Lias, Silurian, etc. Hand colouring was cheap and could cope with the increasing variety demanded by the evolving subdivisions of the geological column with overwashes and stipples to enhance the different shades of the pure colours.
Though the first colour-copy was usually produced, with varying degrees of competence, by the geologist, the draughtsman coloured up the master copy from which the colourists worked.
The copies for sale to the public may have been coloured in part by the Survey draughtsman though many were hand-coloured by out-workers — often ladies — who earned their remuneration by the meticulous copying of a master on to a batch of black and white 'pulls'. As the selling price of these hand-coloured maps was only a few shillings, the hourly rate for colourists must have been a few pence!
The first colour printed maps were produced in 1898 by a commercial printer, Wyman and Sons of Caster Lane in the City of London. They were on the 4 miles to one inch scale Ordnance Survey base and covered England and Wales in twelve large sheets. They were lithographically printed in up to twenty colours, attempting to copy the hand colours in all their vagaries, including stipples and fault lines in white and yellow, simple in hand colouring but very difficult to reproduce by printing. Colour printing of one inch maps followed soon after this breakthrough.
When Eric Tallis joined the Survey in 1946 he recalls the methods in the Drawing Office as being unchanged since Victorian times. The most advanced technical equipment was a set of American 'Wrico' lettering stencils: the brass and ivory pantograph by Stanley dated from the 1880's; and the 'light box' or 'tracing table' contained about 30 tungsten lamps and in use became hot enough to fry an egg.
The total Drawing Office staff in London at this time was about eight, with five in Edinburgh and one in each of the Manchester and Newcastle offices.The London staff serviced the illustration needs of the museum as well as the routine production of fair copies of one-inch and six-inch maps for publication. These were subsequently re-drawn and printed by Ordnance Survey. As the geologist concerned had made what was called a 'Clean Copy' in Edinburgh, or a 'Standard' in London, before the Drawing Office started, there was a considerable duplication of work.
All the Drawing Office lettering and line work was pen and ink, using metal 'crow quill' drawing pens or two-bladed draw pens which required accurate setting to draw lines of variable width faults were twice as wide as 'geological boundaries'. Six-inch maps were still prepared on a paper base, often in a red ink, 'bleachable carmine', which as the name implies could be removed in case of error or correction with hypochlorite solution. These maps were prepared to a very high standard of lettering and line work geologists at that time were under the impression that these were the master copies from which the published sheets were printed but in fact they were only used by Ordnance Survey as a working copy and were all redrawn in Southampton.
Up to the late forties the one-inch maps were also drafted in this fashion, on paper, but the first innovation in map production in a very long time came with the introduction of the 'enamel plate', the base provided by Ordnance Survey being a pale blue topography on a zinc (later aluminium) sheet sprayed with an egg-shell enamel drawing surface. Unlike paper this was dimensionally stable and could be processed photographically by Ordnance Survey. In the Exhibition Road and Grange Terrace offices, however, the preparation of these geological line maps was still a matter of hand, eye and proportional dividers.
The breakthrough to photographic methods of map production came with arrival of draughtsmen who had some outside - military experience before they joined the Survey, a change from the pre-war trainees.
When presented with an 'enamel plate' and a set of six-inch standards from which to work, Eric Tallis enlisted the help of the Photographic Unit, which consisted at this time of one man with a glass plate camera and an ancient mahogany and brass horizontal enlarger. Jack Rhodes used this equipment to produce excellent black and white field photography, albeit slowly. Tallis used it to photograph the field map 'standards' down to the 11/2 inch to one mile scale of the 'enamel plate' and produced a series of positives on film. With the aid of the National Grid lines, which were on both reduction and enamel plate, he was able to trace accurate geological lines - a day's work using proportional dividers - in a matter of minutes.
With the experience gained from the Army Tallis knew that example was more effective than precept and, sure enough, example was more effective thanprecept and, sure enough, photographic reduction became the standard technique from then on. The fact that it required innovation from junior staff to bring it about, however, illustrates the inbred and limited experience of the senior Drawing Office staff at that time. None had any knowledge of printing methods and there was no liaison with Ordnance Survey at technical level. As a result a lot of effort was wasted, notably in the case of the 'colour patterns' sent to Ordnance Survey to guide the final colour printing of the maps. These were line proofs of the geological map, hand coloured in water colour to the old Geological Survey colour patterns, and were beautiful pieces of work. They were not much use, however, as a guide to the printers and the slight differences in tone on the 'Drift' maps in particular, led to endless trouble and expense in the hundreds of corrections that had to be made to negatives and printing plates.
Following the introduction of photographic methods of reduction, Tallis introduced the system, used elsewhere for many years, of 'stuck-down' symbols and lettering, such as dip arrows and the 'crows' used to indicate river terraces. Instead of being laboriously drawn by hand these were available on transparent film and could be stuck in position with adhesive. Wax was used in the earliest applications and sometimes softened in later processing, giving curious orientations. These symbols and, later, notes and lettering, both on the face of the map and in the surrounding explanations and indexes, were produced by the Ordnance Survey from lists supplied by the draughtsmen, at first by letterpress printing on thin transparent film - 'Clarifoil' - and subsequently on the prototype photo-lettering machines which came into use in the mid-fifties.
By this time, too, the first plastic drawing materials were in use and large scale (six inches to one mile) maps were now drawn on blue impressions of the base on flexible translucent 'Astrafoil' sheets which, when finished by the Drawing Office, could be used for direct reproduction. The days of the 'dry proof' or fair copy, to be laboriously redrawn by the Ordnance Survey draughtsmen, were over at last and the millstone of Victorian lithographic methods had been removed.
With the introduction of new processes and materials, the equipment of the Drawing Office changed dramatically. There was no need for horizontal enlargers any more, with a commercial vertical projector being introduced to change scales of drawing. Photo-lettering machines of increasing sophistication were appearing; although the early models were noisy mechanical clatteiing contraptions, they had the capacity to produce lettering to the specifications required.
All map drawing was now on translucent scale-true base and the ancient wooden drawing boards, pitted with holes from the drawing pins of past generations of draughtsmen, were replaced by illuminated drawing surfaces. The ruling pen and the 'crow-quill' also disappeared, as did the staff's ability to use them! The great achievement of the technical revolution of the fifties and sixties was that material of all sorts — maps at all scales, illustrations — was now leaving I.G.S., as it now was, for direct reproduction, with an end to the enormous load of 'corrections' which had bedevilled the earlier processes. One has only to look at the 'correction copies' of the earlier years to see the wasted effort, with literally hundreds of 'corrections' marked for alteration on the Ordnance Survey redrawn material.
With all this progress, however, one link with the days of De la Beche and Portlock remains. By and large the field geologists still insist on using paper maps. Whatever the cartographic drawbacks there is still nothing so effective for field use and the traditional pencil notes, 'inked in' later, are easily erased and corrected. Experiments with plastic-based 'field slips' in the sixties proved quite unsatisfactory. Whether paper will survive the second technological revolution remains to be seen.
This second period of change, the electronic era, got under way in the early eighties with the acceptance in cartography of the automation of drawing. The introduction of drafting machines into engineering drawing offices was relatively straightforward — at first these were controlled by punched cards or tape and were mainly for redrawing and repetition, — but the advent of the computer, visual display units and light pencils rapidly increased the scope of the new techniques and their introduction into cartography became inevitable.
Now we live in the day of the digitising table and lines on a map become impulses on a coated tape or a 'floppy' disc, to be reproduced on paper or on video screen and manipulated at will. Scale changes now become a matter of electronics and overprinting of, for example, geophysical or geochemical data on a geological base, a straightforward computer programme. The advent of electronic colour scanning and printing by trichromatic colour jet will, no doubt, be the next stage in the automation of map production — but with the accelerating rate of technical advance it is fruitless to try to look into the future. One can only hope that it retains something of the craftsmanship of the nineteenth century copper plates and the hand-coloured tints of that time.
Though mankind had been making maps for centuries, the cartographers, like the printers and engravers all sprang from the monastic scriptorium and carried the ideas of 'craft' and 'mystery' with them. Not until the late fifties of the twentieth century did they start to pool their ideas with the formation of the Cartographic Society, of which Eric Tallis was a founder member. Perhaps the ready acceptance of the new technology is due in part to this new professionalism, though it is nevertheless a sobering thought that while a draughtsman of the 1840's would have been able to take his place at a desk up to the late 1940's with little re-adjustment, a draughtsman of the 1940's would be completely lost in the drawing office of the 1980's.
Though photographs exist of the geological staff from the nineteenth century, there are few, if any, of the draughtsmen, and even the names are forgotten. Apart from the faded initials on the back of the old 'dry proofs' and colour models and on the memoir illustrations, the Drawing Office has no memorial — though as with St Paul's Cathedral and Christopher Wren, it is necessary only to say 'Look about you'.