What does Russian pretreatment liquid mean?

Russian pretreatment liquid is a kind of liquid used in fixing process. It is a part of the black-and-white photography process, which is used to process unexposed film so that the exposed image can be reflected in the photo. It is unique in that it can eliminate the frequent darkening and whitening problems and make the photos clearer.

Russian pretreatment liquid is composed of several chemicals, including sodium sulfite, phenols and alkaline substances. The proportion and formula of these components will vary from manufacturer to manufacturer, but they all have a common purpose: to help directly transform the silver particles on the film, and then remove useless carbonate, so as to ensure that the fine image details are preserved after development.

Before use, it is necessary to pour the liquid evenly on the film. It takes about 15 minutes to scan the film at room temperature, but it takes an extra 5 minutes for processing and cleaning after using Russian pretreatment liquid. Wear gloves and a mask when using, to protect the skin and respiratory system, and to prevent contact or inhalation of liquids. After use, the solution rich in sulfurous acid must be discarded in a special storage container to prevent pollution and environmental pollution.