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| Edwal 4 & 1 Hypo Eliminator, Archival Wash Aid, 1 Pint Makes 4 Gallons |
| Category: Hardware |
Date: 05-09-2005 |
Reduces washing time of both film and print materials by 70 per cent. This is achieved by chemically accelerating the removal of hypo and silver thiosulfate complexes during the wash phase. Edwal 4 & 1 works as quickly with cold water (40F) as with water at room temperature.Helps remove residual silver ions which in time can react with atmospheric pollutants to cause stains.Reverses the formation of insoluble polythionates, converting them to thiosulfates which are easily washed out. These polythionates must be removed, for under humid storage conditions will break down to form silver sulfide stains.Prevents the oxidizing effect of air and chlorine in wash water from causing further polythionate formation.Coats the image silver with a compound protecting the emulsion from attack from atmospheric pollutants, providing image protection only exceeded by selenium or gold toning. It also protects the image against tone changes in the case of treatment in a hydrogen peroxide bath.Edwal 4 & 1 should be distinguished from oxidizing type "hypo neutralizers" which can cause image fading in prints when allowed to soak for prolonged periods of time. 4 & 1 is also different from ordinary "washing aids" which do not remove polythionates, as outlined below.Usage of 4 & 1 will not hinder the effectiveness of dye toners. Archival usage of 4 & 1 makes it unnecessary to use a hydrogen peroxide wash for the processing of prints to museum standards. |
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