tio2 used in paper suppliers

This article discusses the discovery of phosphorescent lithopone on watercolor drawings by American artist John La Farge dated between 1890 and 1905 and the history of lithopone in the pigment industry in the late 19th and early 20th centuries. Despite having many desirable qualities for use in white watercolor or oil paints, the development of lithopone as an artists’ pigment was hampered by its tendency to darken in sunlight. Its availability to, and adoption by, artists remain unclear, as colormen's trade catalogs were generally not explicit in describing white pigments as containing lithopone. Further, lithopone may be mistaken for lead white during visual examination and its short-lived phosphorescence can be easily missed by the uninformed observer. Phosphorescent lithopone has been documented on only one other work-to-date: a watercolor by Van Gogh. In addition to the history of lithopone's manufacture, the article details the mechanism for its phosphorescence and its identification aided by Raman spectroscopy and spectrofluorimetry.

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, 2. The herein-described process for manufacturing lithopone of various grades and a by-product of sodium hydrosulfid, which consists in preparing separate solutions of zinc sulfate and barium sulfid, which solutions are mixed with each other and with that of sodium bisulfate, all in equivalent and calculated amounts to produce and precipitate the desired grade of lithopone and leave the so dium hydrosulfid in solution, substantially as described.

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The global Lithopone market is highly consolidated and a major bulk of Lithopone is produced in China. Some of the major Lithopone producers include Anhui Union Titanium Enterprise Co. Ltd., Fengchen Group Co. Ltd., Henan Premtec Enterprise Corporation, Langfang Pairs Horses Chemical Co. Ltd., Natural Pigments Inc., Noah Technologies Corporation, Titanos Group, VB Technochemicals SA, Venator Materials PLC, and ZhengZhou Sino Chemical Products Co. Ltd.

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