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Updated: May 12, 2025
Expose an impressioned plate, that has been sufficient time in the camera to become solarized, to the vapors of bromine, and the impression will be fully developed and exhibit no signs of solarization. The exposure over the bromine most be very brief. Chlorine or iodine will produce the same result. The latter is preferable.
Thus, when immersing a plate sensitive to all radiations, visible and invisible, in a very dilute solution of nitric acid, bichromate of potash, or hydroxyl, it was shown that if the plate were exposed to light, first the parts acted upon by the red rays were reduced before the parts not acted upon at all by the spectrum, thus conclusively proving that light itself helped forward the oxidation or so-called solarization of the image.
Solarization, and general blueness of all the light parts of the picture, were formerly great obstacles to success, though now scarcely thought of by first-class artists. Beginners in the art, however, are still apt to meet with this difficulty. It is occasioned by dampness in the iodine box, which causes the plate to become coated with a hydro-iodide of silver, instead of the iodide.
If the solarization be very deep, apply the lamp beneath, and warm the plate a trifle. Now pour off, and, without rinsing, apply the gilding. The whole operation must be quickly performed, or the chlorine soon attacks the shades of the picture. When properly done, however, the solarized parts are restored to a clear, transparent white. Electro, or Cold Gilding.
This I am led to believe is occasioned by the action of light on the yet sensitive portions of the plate, and made to appear only by subsequent exposure to mercury, being equivalent to solarization. There has been little said by our professors upon the subject of the position of the plates while exposed to the mercurial vapour. Mr.
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