The international photographer (Jan-Dec 1939)

Finest Rental Equipment In the East! • N. C. Milchell Cameras • Standard Mitchell Cameras • Bell & Howell Cameras • Studio Equipment Blimps • Panoram Dollies • Hi-Speed Equipment • Bi-Pack Color Cameras • Single Systems • Complete Lighting Equipment • Moviolas • Cooke Speed Panero or Astro Pan Lenses WRITE FOR RENTAL RATES Sole Eastern Representatives Mitchell Camera Corp. MOTION PICTURE CAMERA SUPPLY, INC 723 Seventh Avenue New York City Cable : Cinecamera Efficient Courteous Service GORDON BENNETT, Manager ■ EVERYTHING PHOTOGRAPHIC Professional and Amateur ■ "New and Used Equipment Bought, Sold and Rented u ART REEVES Camera Supply Co. 1515 North Cahuenga Boulevard HOLLYWOOD CALIFORNIA Cable Address: "CAMERAS" IUTER^ In U)urlJ"U)id,« Us* produce OOwpnlmhl and (\)iqnf ^ff«f Is id Daytime ~Fvy Scvrr??sUiffused Fo^-us and many wlbereffrcls Gcorae H. 5c hoi bo ORIGINATOR OF EFFECT FILTERS 1927 WEST 7e™ ST. LOS ANGELES. CAL LINING LP METHOD (Basic) A small port shall be included in the rear housing of the lamphouse in line with the optical center of the equipment so that, with no carbon in the mechanism, preliminary lining up may be accomplished by sighting through the carbon jaws and aperture. INTERCHANGEABILITY OF BURNER ELEMENTS (Basic) The burner elements, both the positive and negative, shall be easily removable from the lamphouse in order to replace parts and to facilitate cleaning, and shall be interchangeable between lamphouses of the same type. ASH TRAYS (Accessory): Removable triiys in the bottom of the lamphouse should be provided to catch debris and to facilitate keeping the lamphouse clean. (7) VENTILATION FOR MAXIMUM DEGREE TILT (Basic) The design of the ventilating system shall be such that the ventilation will not be reduced when using the lamp at a maximum angle of tilt of 30° above or below the horizon. (In the opinion of the committee, a 30: angle is the maximum tilt at which it will be necessary to burn the lamp. This angle is greater than the minimum degree of tilt specified on page 2 for the projector, but may at times be reached in operation due to the equipment as a whole being purposely set off -level in some particular setup.) HEAT INSULATION (Basic) The walls of both type lamphouses shall be so designed and treated that the heat will be conducted through the chimney rather than radiated out through the side of the lamp, thus lowering the temperature of the lamphouse. HEAT INSULATION (Auxiliary): It has been suggested, that should the lamphouse not be used with a portable equipment, that a metal cover be provided over the upper part of the lamphouse with sufficient clearance to set up a draft between this cover and the lamphouse to carry the heat transmitted through the lamphouse up the chimney. MATERIALS OF CONSTRUCTION (Basic) All parts of the lamphouse and shield (baffles) shall be constructed to distribute the magnetic flux in a manner that will not disturb the proper burning of the arc. VISUAL INDICATOR DEVICES (Basic) An indicator shall be provided comprising a compact, rigid optical system having a visual target index to show the burning relation between the carbons. An indicator shall also be provided to show the length of trim left in the lamp. METERING FACILITIES (Basic) An accurately calibrated and dependable ammeter and voltmeter shall be provided in the electrical circuit to show the arc current and voltage. (8) Recommendations Applying Only To the Mirror Type Lamphouse CAPACITY (Basic) The lamphouse shall be designed to be convertible to accept either 11mm or 15mm carbons. VENTILATION OF THE LAMPHOUSE (Basic) The ventilation of the lamphouse shall be so designed that the lamphouse will be able to handle as high as 150 amperes without detrimental heating, this to be accomplished with minimum draft at the carbon arc so as not to impair the arc steadiness. (See note, "Flicker," page 4.) SPEED OF MIRROR (Basic) Interchangeable mirrors with speeds capable of filling F2.0 and F1.6 projection lenses shall be provided. (Present mirror reflectors do not produce adequate results in an F2.0 or F1.6 system and efforts to improve this condition should be made.) ADJUSTMENTS (Basic) The mirror shall be provided with universal adjustments so constructed as to maintain their settings. DISTRIBUTION OF LIGHT ON THE SCREEN (Basic) An optical system should be developed to provide a more uniform distribution of light on the screen than is now obtained from mirror type lamps. (See "Capacity of the Feeding Mechanism," page 9.) Recommendations Applying Only To the Condenser Type Lamphouse CAPACITY (Basic) The lamphouse shall be designed and constructed to accommodate 13.6, 16, and 18 mm carbons and to accommodate in the case of the relay setup, condensers (see page 13) capable of filling an F1.6 lens and cover the camera apertures as specified under "The Film Gate and Projector Head," page 16. ADAPTABILITY (Basic) The condenser lamphouse shall be so designed that it wiU be adaptable to a relay condenser system at such time as this system mav be desirable. (91 ADAPTABILITY (Auxiliary): In the opinion of the committee, the basic recommendation on "Adaptability" (bottom of Page 8) will probably call for greater latitude in positioning and adjusting of condensers, and it has been suggested that the front end of the lamphouse be so constructed that will be adjustable to accept different types of optical systems as well as those existing at present and those expected to be developed in the future. One method suggested has been the use of an adapter plate or series of rings on the front of the lamphouse which will allow, at the present time, a stepping down of the size of the openings in the front of the lamphouse to present systems, and the addition of faster systems, at a later date, merely by removing the adapter plates or rings. VENTILATION OF THE LAMPHOUSE (Basic) The lamphouse shall be so designed that sufficient ventilation will be provided for the use of currents as high as 250 amperes without detrimental heating, this to be accomplished with minimum draft at the carbon arc so as not to impair the arc steadiness. (See note, "Flicker," page 4.) Feeding Mechanism and Accessories (Applying to Both Type Lamphouses) CAPACITY OF, AND TOLERANCES IN, LIGHT VARIATION FROM THE FEEDING MECHANISM (Basic) The carbon feeding mechanism shall be designed so that the light projected on the screen is not subject to periodic changes of level attributable to the feeding mechanism (see "Light Variation," page 4), and must be capable of handling the carbon sizes specified under "Capacity," page 8. TOLERANCES (Basic) Feed and contact brushes for the positive carbon shall be so designed and made that the crater, during operation, will not change its focal position by more than ±0.025". The positive head shall be designed so that the positive carbon axis at the crater will rotate within a circle of a radius of 0.010 . BURNING POSITION OF CARBON (Basic) The feeding mechanism shall be so designed that the negative carbon will burn at an angle, in relation to the axis of the positive carbon, to obtain optimum efficiency. With present equipment and carbons this angle is approximately 53°. To Be Continued in the April issue 24