Methods of increasing the particle size of ammonium octamolybdate (AOM) pigment powder are provided. A method can include heating the AOM pigment powder to a temperature above 20° C. for a given amount of time. An ink composition can be produced by formulating AOM pigment powder with increased particle size and incorporating the AOM pigment powder into an ink composition.

Provided are thermochromic color-memorizing composition and thermochromic color-memorizing microcapsule pigment encapsulating the same, the thermochromic color-memorizing composition including: (a) an electron-donating color-developing organic compound; (b) an electron-accepting compound; and (c) an ester compound represented by the following formula (1) as a reaction medium which controls color reaction between the components (a) and (b):

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The novel yellow metal azo pigments based on at least three metal azo compounds, which differ at least in the type of metal, have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds, which differ at least in the type of metal, have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds which differ at least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds which differ at least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds which differ at least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds which differ at least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least two metal azo compounds which differ a least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least two metal azo compounds which differ a least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.