<span>Daguerreotype
The daguerreotype method was invented in the 1830s by Daguerre, a French painter and physicist. He discovered that exposing an image onto a copper plate coated with iodized silver would produce a lasting image if it was also exposed to mercury vapor and fixed with a common salt solution. Later, other vapors were used. Daguerreotypes are captured on polished silver, making it reflective, like a mirror.
</span><span>Calotype
Talbot moved on to another photographic process in which photographic paper was brushed with a salt solution, dried, then brushed with a silver nitrate solution and dried again, creating a silver chloride. Talbot then added gallic acid, making the paper more sensitive to light.</span>
<u>Communications technology</u> consists of both physical devices and software, links the various pieces of hardware, and transfers data from one physical location to another.
