The author warns for accuracy in the study of pigments, whereas, scholars have often relied on heresy or previously published information on pigments that may be inaccurate. Much confusion exists in identifying the same pigments with different names. Often inaccurate synonyms have been used in an attempt to categorize pigments. Art historians and experts in determining provenance could make inaccurate determinations regarding authenticity of paintings due to inaccurate published information regarding pigments. Great care must be used. The period covering the 1850's to the 1940's is likely to be the most difficult period to study in regard to the history of pigments, largely because a great number of synthetic organic pigments were added to the already considerable number of existing pigments.