The agent is a "thiosulfate." There are two in use.
The one we all started out on, because the other is more expensive, is sodium thiosulfate. It comes as a powder you add to water, stir until it dissolves then add more water to make the recommended amount. There's normally some potassium alum in it to harden the Gelatin (fixers for color work don't need this as the emulsion is prehardened in manufacture) and some acetic acid to act as a stop bath.
The one we all should be using is ammonium thiosulfate. It's a liquid so it's easier to mix, it works faster and it's easier to wash out of the emulsion. It also contains hardeners and acids.
Sodium Theosulfate AKA Hypo is one form of fixing agent
Yes, sodium thiosulfate can be a reactant in chemical reactions, such as in photography as a fixing agent or in medical treatments for cyanide poisoning. It can also be used in measuring the concentration of other substances through titration reactions.
Hypo is a reducing agent when combined with Na.
Copper thiosulfate is the chemical name for Cu2S2O3. It is commonly used as a complexing agent in chemical solutions and photography.
Polonium is not used in photography.
Photographic fixing agent. An emulsion of sodium thiosulfate (called hypo by photographers) is used to stop development of exposed film. Thiosulfate converts undeveloped silver bromide grains in the film into water-soluble silver thiosulfate complexes that can be removed when the film is washed.S2O32- + AgBr(s) AgS2O3- + Br-S2O32- + AgS2O3- Ag(S2O3)23-Thiosulfate is also an antidote for cyanide poisoning. It reacts with cyanide to produce sulfite and thiocyanate ions:CN- + S2O32- SCN- + SO32-This reaction is catalyzed by an enzyme produced by cell mitochondria to neutralize small quantities of ingested cyanide (which occurs naturally in cassava root, lima beans, and almonds!).
Sodium thiosulfate is neither an acid nor a base; it is a salt composed of sodium cations and thiosulfate anions. It is often used in photography as a fixing agent to dissolve unexposed silver halide in film or prints.
aluminuim is used in flashlight photography
Police photography is just a synonym for forensic photography
john seale
Some common photography lighting styles used in professional photography include natural light, studio lighting, and flash photography. Each style has its own unique characteristics and can be used to create different effects in photographs.
The idea of permanently capturing an image on a substrate was thought of by Thomas Wedgwood in England, but his early attempts used silver nitrate without a fixing agent, meaning the images could not leave darkened rooms. The first known photograph taken by a camera is credited to French inventor Joseph Nicéphore Niépce, who in 1826 successfully captured a permanent image using a camera obscura.