International projectionist (Jan 1961-Dec 1962)

Dichroic mirror THE VERY FINEST IN PROJECTOR 4635 WEST LAKE ST., CHICAGO, ILLINOIS Heart AM <ai 1 Block from State Street Shopping Air-Condjtioned Free TV Convenient Parking (Auto Pickup & Delivery Service Available) 300 Modern Rooms Modest Rates from $6.50 Guaranteed reservations with your FREE Hamilton Hotel "Preferred Guest" Credit Card — Write for yours today wm RESTAURANT and COCKTAIL LOUNGE Hamilton 20 SOUTH DEARBORN 100 90 80 70 60 50 40 30 20 10 ^ ** *» •_ d % \ * N * / ^—Silver mirror i i 1 1 t • t \ / 1 \ \ 1 1 X V \ \! 4 w \ \ \ ^ W 'v> \ \ V 400 500 600 Nanometers 700 FIG. 7 — The reflection characteristics of a dichroic "cold" mirror are more selective than those of a silver mirror. A cold mirror is a much better reflector of those wavelengths of light to which the eye is most sensitive. Color Factors . . . Continued from Page 9 efficient of reflection over all parts of the visible spectrum except the extreme violet and red ends. (This is why such a mirror transmits a magenta-pink light — red plus violet.) Because the reflection curve of the dichroic mirror represented in Fig. 7 emphasizes the green region of the spectrum, producing a slight coloration which can just barely be detected visually under conditions of direct comparison, the strong blueviolet and red emission of the xenon lamp tends to maintain a natural-sunlight quality of the light when used with a dichroic mirror, as it should be to eliminate heat. It can thus be appreciated that the unusual spectral characteristics of zenon illumination (Fig. 4), rather unsatisfactory in the "raw" state, are modified by the aggregate selective absorptions of the screen, lenses, and dichroic mirror to resemble natural sunlight or Hi-arc radiation. This does not mean that the light of the HI carbon arc is unduly yellowed by these factors, for such yellowing of the light cannot be considered objectionable unless the color of the light appears distinctly yellower than direct noon sunlight (5090° K). The small selective absorptions of the violet and blue wavelengths by the lamp mirror and lenses cannot be altered by the projectionist, but yellowing of the light caused by old or deteriorated screen surfaces can be corrected by the simple expedient of installing a new screen which is truly white, or colorless. The use of pale lavender glass in the projection ports is a satisfactory expedient only in very small theatres having more than enough projection light. iP New PSA Lecture On Slide Improvement "Transparency Overlays" is the title of the newest lecture released by the Recorded Lectures Program of the Photographic Society of America. Produced and narrated by Dr. Louise Agnew, the program shows how slides can be improved by sandwich-binding them with materials ranging from other slides and color tissues, to pieces of lace or nylon stocking. Slides which might otherwise be destined for the waste-basket can be converted into pictures with real impact by the judicious use of overlays to change or create mood, color balance, or emphasis. Dr. Agnew, a resident of Chicago, is an associate of PSA, a fellow of the Royal Photographic Society of Great Britain, and a highly qualified artist who has perfected many of the techniques she demonstrates in this 40-minute, 73-slide presentation. iP NEW MAGNASYNC DEALERS Magnasync Corp., North Hollywood, Calif., has appointed three new foreign dealers, according to an anouncement by D. J. White, president. The dealers are William Over & Co., Pvt. Ltd., Salisbury, South Rhodesia, Photo Agencies Pty. Ltd., Johannesburg, South Africa, and Kerridge Odean Industries, Auckland, New Zealand. At the same time, all previously established representation in Cuba was completely severed. This brings Magnasync's world-wide representation to a total of twenty-two firms. Magnasync is engaged in the design and manufacture of magnetic recording systems for the professional and amateur motion picture fields. 16 International Projectionist January 1961