International projectionist (Oct 1931-Sept 1933)

20 INTERNATIONAL PROJECTIONIST July-August 1933 :rYPE"A''ir"A\/" ecus JENSiriVITYVS YolTASe 4-000 sooo eooo 7000 8000 WAVE LCN67H-ANSSTIIOMS CCLL VOLTASC increase of frequency. Furthermore, the greater the applied voltage (resulting in more gas amplification), the larger is the attenuation at high frequencies. As the frequency increases the dynamic output approaches that of a vacuum cell. There are many other photo-emissive cells employing sensitive surfaces which are sensitive to ultraviolet light. Although their characteristics are interesting, their application at tity of metallic caesium is deposited. The dynamic characteristics of a Caesium reacts with Ae.O to form an .. • i i • ■ oxide of caesium with which a very ^^ photo-emissive cell are shown present is limited to scientific research thin film of metallic caesium is asso ^" ^^^' ^' ^ "^^^uum cell shows essen and a very few semi-commercial apciated. The process is one which re ^^^^^^ uniform response over a wide plications. range of frequencies. The gas-filled quires considerable delicacy of con trol and manipulation but it results in cells which are many times more sensitive to red light than any heretofore produced. A typical color sensitivity response curve of this cell is shown in Fig. 3. [In the next issue Mr. McMaster will „ , , , discuss photo-conductive and photo cell shows marked attenuation with voltaic cells.— Editor. ^l PLAN SMALL TOWN INVASION WITH 16 MM. SOUND-ON-FILM EQUIPMENT both exhibitors and projectionists. FEW STUDIO CHANGES FOR W.E. WIDE RANGE In the same figure is shown the color P^^^S are under way to open up ration after a couple runs, plus the response of the human eye In Fig 4 ^ ^^^* "^^ market for motion pic common fault of difficulty in splicing, is shown the response of the caeshim *"'?-^ ^^ installing 16 mm. sound pro Sound is satisfactory, the frequency oxide rpll tA th^ inr^Kf f. '=^dCMum jection equipment in more than 5,000 range encompassing from 150 to about oxide cell to the light from a tungsten towns which now have no picture ex 4,800 cycles. i?^"^ . . hibitions. Idea has already been sold Food for thought in this plan for I'hoto-emissive cells have a substan to two major film companies (under tially linear current response with re stood to be Fox and Paramount) to spect to incident light intensity as "^® their releases, both feature and shown in Fig. 5 The output of gas ^^°^* subjects, for reduction from 35 filled cells increases with applied volt "i"^ *« 16 mm., with distribution to ,^. , ^. . age until the f K ^ effected through regular booking As far as the studio is concerned, no , f "^^^-^ ^^" fifi'UP with those who will buy the drastic changes are necessary for proacnes a vertical line, at which point sub-standard equipment on the strength W.E. Wide Range recordings. A stuthe ionization becomes self-sustaining of guarantee that ample product will dio that was considered a good studio and the cells glow. This generally re be available. Jack Barry, formerly for sound recordings previously, is still duces or destroys the sensitivity of ^^^^ o^ Publix Managers School, un a good studio for Wide Range recordthe surface and should be avoided by ^^rstood to be originator and prime ing. The new equipment necessary to maintaining the applied voltage below ^°'^^^ ^" P^^" introduce Wide Range can be enumerthe maximum safe voltage given in , ^* '%^fZf^^ *Vt ^^out 5,000 ated briefly as follows: a new lens •Rio 7 Tr-,^,,,, n u ^ , ., towns of 3,000 population each are system, an improved microphone, minor l<ig.7. Vacuum cells, however, exhibit ripe prospects for this plan. Film modifications of the amplifier system a saturation characteristic which is to distributors are expected to glean from and new equalizers. To make the be expected because of the absence of $200,000 to $300,000 extra weekly, with change-over effective throughout the gas. Vacuum cells have roughly one approximately two years being added studio, it is necessary to provide imfifth the output of gas-filled cells but *° *^^ playing time of each subject, proved equipment also for the monitorare more stable and are not critical ^^^^^ches, schools and small audi ing .system and the review rooms, with respect to operating voltage as *°""™s ^^^ ^^^^ b^i"S considered as The modifications of the studio ■ — ^ ^ ' likely spots for such equipment. equipment are not in themselves cornEquipment and Operation plicated. It is highly essential, howEquipment and operating angles of ever, that they should be fully and exthe plan are of interest to projection pertly applied and that the entire Wide ists. RCA is reported to be supply Range recording installation should be ing the sponsors of the idea with thoroughly coordinated inasmuch as complete projection and sound equip only a complete and harmonizing imment. A 500-watt incandescent lamp provement of recording, monitoring used heretofore with this equipment and review rooms can result in the will be supplanted by a 700-watt lamp, full attainment of quality. Sponsors insist that a good 12-foot : picture is obtainable with the equip ivTi-wr /^a/tatta r\r>r»Tiw A^Tr'Tr 4. lii, u ii u I, ij n NEW OMAHA ORDINANCE ment, although other observers hold 9 feet to be the limit. Projectionists and exhibitors of Shows run something over two Omaha, Neb., finally have agreed on hours, with projector reels having a a new city ordinance to govern licens capacity of more than 4,000 feet. So ing of projectionists. Plan passed by called safety stock is used, which the city council provides for a board means the non-observance of all re of examiners composed of a represen strictions as to magazines and operat tative of the fire department, the city ing precautions which apply to nitro electrician and city building inspector. cellulose stock. Reports received by Former board also included one exhi this publication would indicate some bitor and one projectionist. The new measure of dissatisfaction with the law will reduce the 60-day residence "safety stock" on the score of deterio requirement to 30 days. shown in Fig. 6. r iiaz 1" \ VISITKON TYPE "A" \ CELLS \ PLUX.-LIM/T-VOLTA6E V CHAKACTCKISTIC \ FIG.7 70 7S SO as 90 »AX.SAFE OFEHKriNd VOLTAt iE 1 dAS FILLET) CELL \l>YNAMIC TtES-pONSE iO xo so to FKEQUENCY-KIUOCYCLES