Abstract: A set of standard materials, which comprises at least two kinds of standard materials, for calibration of a photoelectric colorimeter used for the instrumental measurement of petroleum products for their ASTM color, comprising at least two kinds of standard materials each of which is a mixed solution having a color corresponding to an ASTM color and comprises (a) at least five members selected from the group consisting of seven specific colorants such as 3-methyl-1-phenyl-4-(phenylazo)-pyrazol-5-ol, 1-(phenylazo)-2-naphthalenol and 1-[[4-[(dimethylphenyl)azo]dimethylphenyl]azo]-2-naphthalenol, (b) 1-phenyl-1-xylylethane as a solvent for said colorants, and (c) dodecane as a diluent; and a method for instrumental measurement of petroleum products for their ASTM color by a photoelectric colorimeter, which comprises calibrating the photoelectric colorimeter by the use of said at least two kinds of standard materials.

Abstract: A standard sample for use in an instrumental measurement of ASTM color of a petroleum product with a photoelectric colorimeter, which comprises a mixed solution 3-methyl-1-phenyl-4-(phenylazo)-pyrazol-5-ol, 1-(phenylazo)-2-naphthalenol, 1-[[4-[(dimethylphenyl)azo]dimethylphenyl]azo]-2-naphthalenol, 1,5(or 1,8)-bis[(4-methylphenyl)amino]-9,10-anthracenedione, 1-hydroxy-4-[(4-methylphenyl)amino]-9,10-anthracenedione, 1,4-bis(butylamino)-9,10-anthracenedione and 1,4-bis[(4-butylphenyl)amino]-5,8-dihydroxy-9,10-anthracenedione each as a colorant, 1-phenyl-1-xylylethane as a solvent for said colorants and dodecane as a diluent, and a method of instrumental measurement of ASTM color with the standard sample.

Abstract: A standard sample for use in an instrumental measurement of Saybolt color of a petroleum product with a photoelectric colorimeter, which comprises a mixed solution of 1-(phenylazo)-2-naphthalenol, 3-methyl-1-phenyl-4-(phenylazo)-pyrazol-5-ol and 1,4-bis(butylamino)-9,10-anthracenedione each as a colorant, 1-phenyl-1-xylylethane as a solvent for said colorants and dodecene as a diluent, and a method of instrumental measurement of Saybolt color of a petroleum product, which comprises calibrating a photoelectric colorimeter with the standard sample.