which chemical makes it possible for a photograph to be exposed to be open to white light
silver halide
title: Photographic paper text: Photographic paper Photographic paper is a paper coated with a light-sensitive chemical formula, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present. The light-sensitive layer of the paper is called the emulsion. The most common chemistry was based on silver salts (the focus of this page) but other alternatives have also been used. The print title: Lead(II) iodide text: Lead(II) iodide Lead(II) iodide or lead iodide is a salt with the formula . At room temperature, it is a bright yellow odorless crystalline solid, that becomes orange and red when heated. It was formerly called plumbous iodide. The compound currently has a few specialized applications, such as the manufacture of solar cells and X-ray and gamma-ray detectors. Its preparation is a popular demonstration in basic chemistry education, to teach topics such as double displacement reactions and stoichiometry. It is decomposed by light at moderately high temperatures and this effect has been used in a patented photographic process. Lead iodide title: Whiteprint text: the copy. Once this process is complete, the undeveloped image at the locations where the UV light could not penetrate can often be seen as very light yellow or white marks/lines on the diazo sheet. This completes the exposure phase. Next, the original is peeled from the diazo paper as the sandwich of master and diazo exits the machine, and the diazo sheet alone is fed into the developing chamber. Here, fumes of ammonium hydroxide create an extremely alkaline environment. Under these conditions, the azodyes (couplers) react with the remaining diazonium salt and undergo a chemical reaction that results in title: White text: all the buildings of contemporary architect Richard Meier, such as his museum in Rome to house the ancient Roman Ara Pacis, or Altar of Peace, are stark white, in the tradition of Le Corbusier. Light is perceived by the human visual system as white when the incoming light to the eye stimulates all three types of color sensitive cone cells in the eye in roughly equal amounts. Materials that do not emit light themselves appear white if their surfaces reflect back most of the light that strikes them in a diffuse way. In 1666, Isaac Newton demonstrated that white light title: White text: could be broken up into its composite colors by passing it through a prism, then using a second prism to reassemble them. Before Newton, most scientists believed that white was the fundamental color of light. White light can be generated by the sun, by stars, or by earthbound sources such as fluorescent lamps, white LEDs and incandescent bulbs. On the screen of a color television or computer, white is produced by mixing the primary colors of light: red, green and blue (RGB) at full intensity, a process called additive mixing (see image below). White light can be fabricated using light