Science for the Curious Photographer, 2nd Edition

APPENDIX G Capturing Photons with Photographic Film

 

 

The discovery of photography in the early 19th century was essentially the discovery that certain silver salts, e.g. silver chloride (AgCl), silver bromide (AgBr) and silver iodide (AgI), are affected by light and can be processed to amplify the effect and make it permanent. These silver salts, known as silver halides, form crystals that visibly darken when exposed to bright light; the process continues so that in the presence of light the crystals get darker and darker. This darkening effect is neither very sensitive nor stable and is not very useful for recording images. The enabling discovery for photography was that chemical processing, after exposure, can convert some of the exposed ...