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Negative -type: They cannot, therefore, conduct an electric current. If, however, one of the silicon atoms in the structure is replaced by an atom with five outer electrons—such as phosphorus— only four of the phosphorus electrons can link up with the silicon atoms; the fifth electron becomes free to move, and this motion produces a flow of current. Silicon containing an impurity that has an "excess" electron is called n-type (negative -type-type) material to indicate the availability of electrons, which carry a negative -type charge.The dots appear in varying size, depending on the tones of the original photographs. A negative -type copy of the picture is first made with a camera, inside of which is fitted the halftone screen. This negative -type is then printed on a metal coated with bichromated gelatin. The dots on the negative -type allow light to penetrate and render the glue insoluble, so that when the plate is etched with acid each single dot remains on the surface of the plate, which is then mounted at type height on a wooden block. In the final print the minute clusters of dots cannot be distinguished, but appear as tones of gray.
5. Never be too proud to reshoot a poor negative -type. Did you make an error in exposure? Did your tripod slip and cause a fuzzy negative -type? Or did you make one of the other dozens of errors which can almost but not quite ruin a negative? If so, do not try to cover up by struggling with the negative -type by means of darkroom trickery, but instead shoot the picture over again if that is at all possible. To reshoot is to confess a measure of failure to "your client, of course, but you can make up for that by going all-out for a masterpiece on your second try. |
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