Editing Daguerreotype (section)

==== Becquerel variation ====
In the [[Edmond Becquerel|Becquerel]] variation of the process, published in 1840 but very rarely used in the 19th century, the plate, sensitized by fuming with iodine alone,<!-- the process was also used as a latensification step before mercurial development by some practitioners (Southworth & Hawes?) who surely did not limit themselves to iodine sensitization, so the modern claim of incompatibility with other sensitizers may be erroneous --> was developed by overall exposure to sunlight passing through yellow, amber or red glass. The silver iodide in its unexposed condition was insensitive to the red end of the [[visible spectrum]] of light and was unaffected, but the latent image created in the camera by the blue, violet and ultraviolet rays color-sensitized each point on the plate proportionally, so that this color-filtered "sunbath" intensified it to full visibility, as if the plate had been exposed in the camera for hours or days to produce a visible image without development. Becquerel daguerreotypes, when fully developed and fixed, typically take on a somewhat bluish hue. The image quality may not be as magnificently sharp as a daguerreotype developed using mercury vapor, although modern photographers pursuing daguerreotypy tend to favor the Becquerel process due to the hazards and expense of working with mercury.