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WRS MOTION PICTURE AND VIDEO LABORATORY |
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1000
Napor Boulevard,Pittsburgh Pa 15205 |
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WRS MOTION PICTURE AND VIDEO LABORATORY |
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1000
Napor Boulevard,Pittsburgh Pa 15205 |
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A and B Wind Emulsion Positions
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The terms "A" and "B" wind properly refer to the manufacturer’s winding of single perforated 16mm raw stocks. These terms have also become widely used to designate the emulsion position of both 16mm tracks and picture elements. Because of this widespread usage with reference to emulsion position, it is important that it be explained. A and B Wind Positions
Contact Printing In contact printing, emulsion to emulsion, the image position of the finished material is always opposite of the image position of the printing material. The wind of the film alternates from "A" to "B" or "B" to "A" in each succeeding generation. In contact printing of titles, make sure your title is in the same emulsion position as the preprint material that you are using. Optical Printing In optical printing it is possible to print the picture in either the same image position or in the opposite image position of the preprint material. When ordering materials to be made optically, you must specify the wind you require, either "A" or "B", of the material to be made. 16mm Prints A 16mm positive print can be either "A" or "B" wind. A print projected with the emulsion away from the lens is "A" wind, and with the emulsion toward the lens, "B" wind. "A" wind prints and "B" wind prints require different focus positions of the projector lens and, therefore, should not be spliced together. 35mm Prints "A" wind and "B" wind terminology is not used in 35mm, although the same changes in emulsion position occur. This is possible because 35mm printing follows an exact set of standards in which negatives, whether original, duplicate negatives or CRI’s, all read through the base. 35mm master positives always read through the emulsion. A standard 35mm release print reads through the emulsion, and is projected with the emulsion towards the light source. When making 35mm prints or intermediates, the proper emulsion position is maintained automatically by contact printing emulsion to emulsion. The only exception is in making a CRI, and to maintain the proper emulsion position the CRI must be printed optically or with base to emulsion in a contact printer. If this must be done, a specular light source in the contact printer will help to maintain sharpness.
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