FAIRLY RAPID  ACCESS

by John Anderson, Long Melford

From East Anglian Federation of Photographic Societies`  Winter 1997 Bulletin, with the kind permission of Editor Mike Neville, LRPS.

Photographers active between the middle 1930`s and the early 1950`s  must remember Dufaycolor with affection, tinged perhaps with frustration. Affection, because extremely impressive results were obtainable; frustration, because towards the end of the 20-odd years of availability, quality, in roll-film at least, became unreliable.

The 500 lines/inch ruling of the filter mosaic was fine  enough to be quite unobstrusive at ordinary viewing distances when 6x6cm or larger transparencies were projected - the difficulty was the amount of light needed. With 35mm slides the mosaic, in relation to  frame size, would be comparable in scale to the scanning lines of a TV picture, 16mm movie film was available for amateur use; examples occasionally appear on television in historical compilations,the mosaic being clearly visible on occasional frames. The film industry made some use of 35mm stock, mostly for "shorts"; in this application, negative-positive processing was used.

The normal reversal processing procedure was simple and at 21 mins at 65 deg F, plus 15 minutes wash, far quicker than the first user-processing procedures from Agfacolor-type materials, such as Ferrania, in the middle Fifties. These took about 85 min at 65 deg F. In 1953  Ektachrome  processing took some 70 min at 75 deg F.

The nominal speed of Dufaycolor  was 8 ASA, similar too the colour materials of its day, but given flat lighting it could be pushed a couple of stops. This capacity was never, as far as I recall, published as such but the use of a desensitiser followed by factorial development - a technique surely long forgotten - was a method recommended by the manufacturers. Some users exposed very generously and curtailed first development, achieving great brilliance of rendering.

An incidental advantage of Dufaycolor overall present-day colour materials was the possibility of reduction and intensification. Reduction of an underexposed transparency was seldom much use, but intensification could dramatically improve a thin, washed-out looking result, provided there were no "burn-out"areas.

Members of the King`s College London Photographic Society made an enterprising use of the comparatively rapid processing in 1950. On the afternoon of Thursday, November 9 the Lord Mayor`s  Show was to take place; the  procession would pass along the Embankment, past the back of of the College. It was customary for students to observe the procession closely, drawing attention to any improprieties of dress in the military units marching past and assisting them in keeping accurately in step. At that time a very large proportion of students were ex-service and so had expert knowledge of such matters. They would also loyally greet the new Lord Mayor, from whom grateful acknowledgements might afterwards be received.

Several members of the King`s College London Photographic Society possessing 35mm cameras were then supplied with short lengths of Dufaycolor,and they duly photographed the event.

I have no doubt the Metropolitan Police displayed their customary concern for the safety of the varied photographers` gear at such events ("Move along now sir please, we wouldn`t want your cameras to get broken"), but no cameras were ever broken and no cameraman arrested.

other members of the Society then took over as darkroom staff and within half an hour strips of film were hanging up to dry. We were not concerned with the "archival permanence" and most probably cut short the final wash. An hour later the slides were dry and mounted, ready  to show at the regular weekly meeting of the Society that evening.

The results as I recall, were outstanding neither as photojournalism nor as colour photography, but it was great fun and I still think it was a worth doing.

LETTER TO THE EDITOR

"A Folio For All"

Just a few lines hopefully to encourage some more members to join the Club Folio, which has lost some members over the recent few months.

In case any member feels that this is a club activity which should be (or is) confined to qualified chemists and full member of the Royal Photographic Society, I can assure you that this is not the case. I am not an expert in either processing or slide photography, I will never weigh & Mix or is my output of films likely to exceed 6/8 per year, and I had some misgivings before joining the Folio. I have never regretted, it is great fun and comments on your own slides are always helpful and constructive. The arrival of the Folio package every 6/8 weeks is always a treat, and it costs nothing more than the postage involved in passing the Folio on to the next member.

My advice to Club members is to give it a try- I am sure that you will agree with me if you do.

                                                                                                                                                                                          Brian Murphy (Area 15).