The international photographer (Jan-Dec 1939)

SCREETT SIZE 8' x 10' 10' x 12' 12' x 16' 16' x 20' LETTS 3" 4" 4£" 5" 6" 20' 24' 32' 40' 30' 36' 48' 60' 40' 48' 64' 80' 45' 54' 72' 90' 50' 60' 80' 100' 55' 66' 88' 110' 60' 72' 96' 120' FOOTAGE SCALE FOR DI3TAITCE FROM IMS TO SCREEN" CHART A Thus, the height of the screen being 12', a 12'xl6' screen is used for proper unity magnification. The next step is quite difficult to do on purely scenic or landscape backgrounds because it is hard to find definite lines leading to the vanishing points. Few people can recognize the proportion between rocks and trees on this type of background. Architectural subjects require particular care because even the laymen are so familiar with such subjects that they can readily trace the vanishing lines and become conscious of the horizon and vanishing points; and the slightest error in the convergence of these lines becomes very apparent. Chart B is the mapped out plan showing how the measurements are brought about. Draw the lines a and a' until they intersect at the horizon. This is the vaning point marked, v. p.1. Draw the lines b and b' until thev intersect at their respective vanishing point, v. p.2 Establish the horizon, H by connecting v. p.1 and v.p.2. Describe an arc or construct a half circle with c as the radius and the vanishing points the diameter. The picture is then divided in the center by the vertical line e and this line is carried down to where it intersects the arc d at the point marked f. Connect f with h and h'. The lines marked g and g' represent the visual angle of the lens which is to be further proved. This may be further proved in the following manner. With v.p.1 as a point describe an arc from f to the horizon which point is marked measuring point, m.p.1; and with v.p.2 as a point describe the arc to m.p.2. From m.p." draw a line to the right-hand lower corner of the picture, k; from m.p.1 draw a line to the left-hand corner of the picture, k' The sum of the angles 1 and 1' equal the angle m. If n and n' equal the motion picture horizontal dimension, then o-f equals the focal length lens used This entire procedure may be done in the enlarger by drawing the vanishing point lines a and b, establishing the horizon line h, establishing the four corners of the picture, and doing the rest of the calculations from those points without further use of the enlarger. It may readily be seen that to establish the camera angle, the distance the horizon line moves above or below the dividing line of the picture gives the exact tilt of the key plate camera. Careful note should be made as to the type of camera used in photographing the key plate: whether it was the Bell and Howell or Mitchell. It is essential that if the key plate was made with the Bell and Howell camera, it should be projected with the pins in the Bell and Howell position at the top of the aperture, the large register pin at the right. If the plate was made with the Mitchell camera, it should be projected with a movement having the pins at the bottom A note can be made while the print is in the enlarger concerning whether it is full aperture or the Academy aperture. In summing up, unity magnification, the focal length of the lens, the camera angle, the tvpe of pins, and the size aperture that the key plate was shot with have been established, which is the same information that can be recorded by the cameraman as stated in the preiovus section. But it may readily be seen that this second method takes time and much trouble to work out and can be entirely avoided if the key plate cameraman records the necessan information at the time the key plate is shot. Section 3: Contrasts of the Key Platj The key plate print should always bt printed on Bell and Howell perforations The natural tendency of the film in re photographing the key plate is to increast its contrast. A normal print, therefore appears much too contrasty in relation t< the actors or scenic foreground placed ii front of the projected background. T< overcome this ,the print should be madf similar to a lavender In other words to obtain the same effect, the print shouk be printed a couple of points heavier oi the printer and developed to a lower gam ma than a normal print would receive To the eye this print appears somewha lacking in contrast but should show al of the detail. The glycin formula is recom mended for the developing of the key plat for the following reasons: it precipitate a fine grain, it develops richness in th highlights, it has brilliant transmissioi qualities and rich detail in the shadow without blocking them. Following is th glycin formula: Water Sodium Sulphite Potassium Carbonate Glycin One or two drops of 10% Potassium Bromide solution The negative should be of normal gan ma but the positive should have a cor siderably lower gamma. Section 4: The Set-Up With all these vital elements havin been predetermined, the operation shoul be to go on the set and get started wit the least possible difficulty With prope direction, the efficiency of such a metho is so greatly increased over the "I hop it looks right" system, that it is boun to save many dollars in production cost: With this information, the process dim tor can step on the stage, line up with minimum of delay, and by referring t Chart A. he can determine the distano according to the focal length of the lens place the projector for the size screen h wishes to use, and check for unity magn fication. He may then further check h calculating the foreground objects to thos of the projected picture. The selection of lens for the projectc has some important points which it woul be well to mention. A long focal lengt lens greatly decreases some of the hot sp< trouble but gives a flatter focal field. Focusing; the projector on the screen ca best be done by standing close to th screen and as the operator focuses th' lens, watch for the prismatic color cor ditions on each side of a minute point o the screen until they show equal balanct 30 ozs. \Vi ozs. 2V-2 ozs.