If a Glass be Immersed too soon, streaks and waves will be occasioned. These will be seen at the end of the plate which is least dry: the coating is also more liable to peel off. It should be borne in mind, however, that the peeling of collodion is not always attributable to this cause.
Diffused Light in the Developing Room.—In proportion as the sensitiveness of the plates increases, greater care must be exercised in thoroughly excluding all rays of white light. With opalescent films, neutral, this cause of fogging is more common than any other.
Tn the case of a portrait, if the features have an unnaturally black and gloomy appearance, the dark portions of the drapery, &c., being invisible, the picture has been underexposed in the camera.
HELIO PROCESS.[F]
[F] It has been thought advisable to publish in this work the Helio Process, and I do so just as it appeared in Humphrey's Journal.—S. D. H.
An Entire Process for Producing Collodion Positives and Negatives with one Bath, and in much less time than by any other known Process.—By Helio.—Photographic Patents.
Boston, Oct., 1856.