<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31373687</termId><termName>sodium thiosulfate</termName><termType>PT</termType><termNote><![CDATA[ A chemical compound with the property of making silver salts water-soluble. This property was discovered by Sir John Herschel in 1819, who recommended it as a fixer in photographic processing. It is also used in conservation practice as a cleaning agent for silver and silver-gilt surfaces, and removing silver chloride from wet-washed paper and wet-washed textiles. ]]></termNote><termCreatedDate>2026-03-30 20:40:46</termCreatedDate><relation><relationType>UF</relationType><termId>31373688</termId><termName>hyposulfite of soda</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31373689</termId><termName>thiosulfate, sodium</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31343447</termId><termName>sodium compounds</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31320037</termId><termName>fixer</termName><termType>PT</termType></relation></term>  </Zthes>