Other black pigments

Black antimony sulphide (Anzon) has a strong black colour and is of interest as a pigment in plastics such as PE. polyesters, and PVC. It also confers flame-retardant properties. It comes as a pulverized treated ore (as a soft powder) or as a chemically precipitated sulphide (as a dried filter cake). Materials have a 

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Pliny mentions other black pigments used for various purposes—bitumen for painting statues and protecting copper vessels 40 burnt ivory (boneblack) and a black obtained by dyers a black inflorescence which adheres to the brazen dye-pans (copper oxide). The saepia also secretes a black liquid, but from this he says no color is prepared. That black oxide of manganese was used by the ancients as a pigment, we know from analyses already referred to, but no clearly recognizable reference to this substance has been identified in the ancient authors. 

Pigment blacks have a number of advantages compared to other black pigments and black organic dyes ... 

Consumer articles often use colorants (qv), reodorants, or finishing agents. Carbon black (qv) provides the best technological properties for industrial appHcations, so most mbber articles are black. Red iron oxide or other inorganic pigments are used to color mineral-filled articles. Organic... 

Other spherical fillers include carbon black. This has several roles particularly in combination with elastomers, e.g., black pigment, anti-oxidant and UV stabiliser, reinforcing filler, and an electrical conductor when used at 60% concentration. Wood flour is particularly effective in phenol/formaldehyde and melamine or urea/formaldehyde thermoset resins because the phenolic lignin component in the wood reacts with the methylol groups (-CH2OH) in the growing polymer. 

P.V.29 types demonstrate excellent weatherfastness, much more so than other perylene pigments. Their impact on the market, however, is limited by their very dull shade of maroon. Full shades are deep brown, almost black. The pigment is very fast to organic solvents and overcoating. Commercial types are utilized especially in metallic finishes. Full shades frequently bronze upon exposure to weather. 

Carbon is an important reinforcing agent for various elastomers. It is used in tires (71%) and other elastomers (22%). Miscellaneous applications (7%) include its use as a black pigment in inks and paints. 

Quality and Intensity of the Colour.—These are determined by the general methods, particular care being taken to note if the colour is a pure black or if it shows more or less traces of brown, reddish, greenish, etc. as regards the intensity, it is well to examine black pigments—always in comparison with a typical black—with reference to their behaviour when mixed not only with a white but also with other pale pigments. 

Other Tests.—In some cases a small quantity of Prussian blue is added to black pigments and especially to soot black to correct any tendency to reddish brown. This may be detected by boiling the pigment with alkali and filtering, and treating the filtrate, after acidification, with ferric chloride, which gives a blue precipitate. 

Chronic idiopathic jaundice, which is characterized by heavy black pigmentation of the parenchymal cells in the centrilobular zones of the liver, differs from other forms of familial jaundice so far described in that conjugated bilirubin as well as unconjugated bilirubin is present in the plasma and bilirubinuria occurs. The type of conjugated pigment in the plasma has not been characterized, and up to the present no adequate explanation for the jaundice has been put forward (D6). 

Gastrointestinal Effects. Minimal information is available on the gastrointestinal effects of human oral exposure to PAHs. In one study, humans that consumed anthracene-containing laxatives (the anthracene concentration was not specified) for prolonged periods of time were found to have an increased incidence of melanosis of the colon and rectum (i.e., unusual deposits of black pigments in the colon and rectum) compared to patients who did not consume anthracene laxatives. However, no definitive conclusions can be drawn from these results because of study limitations that include possible misclassification of patients with respect to the level of anthracene laxative use over 30 years and no accounting for other factors involved in the pathogenesis of melanosis (Badiali et al. 

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