Luggin.īy exposure the surface and the interior of a silver-bromide sphere will disintegrate by the expulsion of bromide. Luppo-Cramer in 1911, based on research by F. The regression process theory was formulated by H. Many explanations have been given but until further notice, the solarization was until 1929 generally understood as a combination of two main processes: the coagulation (clotting) and the regression process. In general, it can be stated that solarisation can only be observed if the photographic layer is capable to create a latent image inside the halide grain underexposure by actinic radiation. Pure Chloride and Iodine based silver emulsions are difficult or unable to solarize. Not every photographic layer exhibits solarization. In 1880 Janssen had obtained in the strongest sunlight a repetition of the solarization phenomena. and recently I have obtained in fact on occasion a third image which is negative". Ludwig Moser reported in 1843: ".that the light in the camera obscura produces at first the well known negative image with continued action of the light the image turns into a positive image. The result was seen as unsatisfactory because the solar disk (image of the sun on the daguerreotype plate) was overexposed and solarized. Lerebours observed the phenomenon in 1842 (without him recognizing what it was) when he made a daguerreotype of an image of the sun. Herschel already observed the reversal of the image from negative to positive by extreme overexposure in 1840. John William Draper was the first to call the overexposure effect solarisation. The solarization effect was already known to Daguerre and is one of the earliest known effects in photography. The exposure to achieve solarization can be increased by exposure time or by increasing the light intensity History In general is the phenomenon only then called solarization if the exposure has been produced in one "shot", meaning no pauses or double-exposures. When a photographic layer, suitable for solarization (see below), is exposed to actinic radiation, the resulting darkening after development will not increase steadily, but reaches a maximum which decreases under more intense exposure. Ansel Adams had also earlier created a solarized sun image, titled Black Sun, Owens Valley, California, 1939, by overexposure. For instance, Minor White's photograph of a winter scene, The Black Sun 1955, was a result of the shutter of his camera freezing in the open position, producing severe overexposure. The sun, instead of being the whitest spot in the image, turned black or grey. Most likely, the effect was first observed in scenery photographs including the sun. In photography, solarization is the effect of tone reversal observed in cases of extreme overexposure of the photographic film in the camera.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |