The Art of projection and complete magic lantern ... - Yesterday Image

99without doubt, this is the only true method by which a series of photographsmay be made to register dead true, only those who have tried cancomprehend the almost hopeless task of trying to make slides with cushionmats to superimpose, the slightest strain on any one side of the matbeing sufficient to throw it out of the square ; with circular mats there isnot quite so much trouble, even then, if exactness is required each slidemust be blocked, a difficulty which these carriers overcome.The Docwra carrier is so constructed that either square or circularpictures can be placed on the screen with such dead accuracy that nocritical observer will see where the one begins and the other leaves thescreen. The mechanical parts are so arranged, that by compressing aprojecting button the slides are gripped automatically and held firmlyagainst the front of the carrier, to ensure each picture being in focus,and are so geometrically true that perfection is attained which cannotbe accomplished by any other means.A is the thumb press that presses the clips back which hold the slide inposition, to place a slide in the carrier hold it at a slight angle, with thebrass face undermost, drop the slide into its place, pressing the spring atthe same time, by this means the slide is held firmly in position andpressed to the front of the frame; to make sure of the slide being down onto the bed of the frame, always press the spring once or twice in succession.B is the regulating stop, for adjusting the distance the frame shall gointo lantern, as it presses against the lantern stage.SCREENS.A great deal of the result is dependent upon the screen, it should hangperfectly flat, and be of snowy whiteness. Many an exhibitor will sacrificehis light by using a screen of a yellowish or dirty nature, in fact beforenow, a domestic sheet from the bed room has done duty as a screen.The best screen for general purposes, especially for travelling, is of a linentexture, scrupulously white and above all very thick and strong, especiallyfor the larger sizes, the thickness gives it opacity, and the strength preventsthe risk of splitting, the corners should be strengthened with an extralayer of strong linen. In the large sheets there is a very great strain onthese corners, some are made with eyelet holes along thetop and sides,others with rings along the top and tapes along the other three sides.prefer the latter, it is entirely a question of use, as many exhibitors preferthe eyelet holes. A public exhibitor usually has three screens, 12, 16,20 feet, as it is not always possible to use the larger screens, even in largeG2We