British Kinematography (1951)

9Q BRITISH KINEMATOGRAPHY Vol. 18, No. 3 being proportional to the magnification, each increase in magnification necessitates increased camera speed, and the limit of camera speed may soon be reached in certain cases. Increase of magnification also requires increased illumination, but difficulty is not expected in this direction except at high powers, and little work has been done in this field. Conclusion The above remarks form a brief resurru: only of the advantages, uses and methods of using the film in research, and it is anticipated that as these become more widely appreciated, both by industrial and scientific research workers, the film will assume an increasingly important position in the equipment of the investigator. REFERENCES 1. J. Yivi£ : Histoire et Developpement de la Technique Cinematographique . 2. J. Soc. Mot. Pic. Eng., 47, No. 6, June 1947, p. 554 ; 54, No. 2. Feb. 1950, p. 140. 3. /. Soc. Mot. Pic. Eng., 52, No. 3, Mar. 1949, Part II, p. 71. 4. /. Brit. Kine. Soc, 7, No. 4, Oct. 1942, p. 114 ; /. Soc. Mot. Pic. Eng.. 43, No. 5, Nov. 1944, p. 321 ; 52, No. 3. Mar. 1949. Part II ; 53, No. 5. Nov. 1949 ; 54, No. 5. May 1950, p. 603 ; 55, No. 2, Aug. 1950, p. 158 ; 55, No. 6, Dec. 1950, p. 613. 5. Func. Phot., 1, No. 11, Aug. 1950, p. 22. 6. Brit. Kine., 15, No. 2. Aug. 1949, p. 56. 7. Brit. Kine., 16, No. 3, Mar. 1950, p. 93. 8. Func. Phot., 1, No. 11, Aug. 1950, p. 7; 2, No. 2, Nov. 1950, p. 18 ; 2, No. 3, Dec. 1950. p. 19. 9. Substandard Film, Mar. 1950, p. 10. DISCUSSION Mr. L. Townes: I notice your films have very fine gram. What stock do you use? The Author : Super-X reversal film. There would be no difficulty in securing more light if we wished to use a finer-grained emu.sion. Miss Thora James : Is there any possibility that public money will be available for making films of this type? The Author : I do not know of any funds that provide money for this work. Films can be divided into two categories : industrial and research. The interesting things like penicillin, thermometers and watches are more academic, and there is not much money available. We are making some films for television, the reason being that te.e vision cannot employ time-lapse methods. Mr. Blay : Has the sound film any application in research other than for commentaries? The Author : I do not know of any. Mr. L. Kxopp : Recently I saw a film at the Royal Society, taken by the Official Astronomer of the Academie Franchise, of atomic disturbances on the surface of the sun, and the pictures were synchronised with short-wave interference signals received through a normal radio set. Mr. R. Ff. Cricks: A high-speed camera now being made has provision for recording vibrations associated with certain phenomena. Recently we saw a remarkable American film showing the beating of a fly's wings, taken with high-speed flash. The Author : I have no experience of stroboscopic illumination. My impression is that there is often a considerable variation in intensity of the light — the flashes are not uniform. The necessary equipment is probably exceedingly expensive. It is simple to make an electric circuit that will discharge every half-minute, but a rate of 3,000 flashes per second necessitates very bulky equipment. An application of sound that I had forgotten to mention was in recording the action of the tongue in speech. A patient had lost nearly all his cheek, and the action of the tongue was filmed at high speed, and the man's speech was recorded, per mitting the therapists to analyse the film with a complete sound track. Mr. Blay : For timing, have you considered the use of a medium frequency oscillator, perhaps 1,000 c/s, for recording on the film? The Author: I think it is probably a more complicated method than the tuning fork, which is relatively simple, and works off a l'2v. battery, with no valves. Mr. Haybittle : Recently I saw a demonstration of the electro-myograph, which records on tape the voltage that is produced in a muscle. The record is fed to an oscillograph, and the oscillograph is photographed. Mr. Clark: In the film on bacteria there were some smaller bodies which remained active. Do vou know what they were? The Author: I think they were very small particles moving about by Brownian movement in the liquid. They were not necessarily living organisms. Mr. N. Leevers : I was very impressed with the use of the film in showing the performance of highspeed mechanisms. In this industry we have a particular interest in that. One of the bugbears of kinematography is the acceleration and deceleration involved in the camera and projector. As far as I know there has been very little effort to discover exactly what happens in a camera gate under working conditions. The high-speed film seems the ideal medium to study it. The Author: So far as I know there has not been much work on the subject in this country. I remember a paper in the S.M.P.E. Journal on the action of fne film in the gate of a projector and the effects due to heat. Mr. L. Townes : In running high-speed cameras, do you get any trouble with heat generated frictionallv in the camera? The Author: No, it is all over too quickly. The thing that would get hot is the motor ; it is a 32v. motor run on HOv. We can take twenty runs in a morning and the motor does not even feel warm,