Methods and compositions for removing precipitates or reducing the formation of precipitates generated in hematoxylin solutions. The methods and compositions feature cleaning solutions that feature chemical compounds that initiate processes including but not limited to acidification of the waste solution, chelation of metal ions in the waste solution, reduction reactions, oxidation reactions, and metal salt addition reactions.

An object of the present invention is to provide an innovative quinacridone pigment that can exhibit even better viscosity stability than conventional pigments and also maintain high saturation in aqueous IJ ink uses. The quinacridone pigment of the present invention has a specific surface area ratio between water vapor and nitrogen of 0.270 or more and less than 0.430. The pigment dispersion of the present invention contains the quinacridone pigment and a solvent. The aqueous inkjet ink of the present invention contains the pigment dispersion.

The problem addressed by the present invention is to provide a high heat-resistant phthalocyanine. The phthalocyanine is separated by mixing a phthalocyanine separation solvent and a phthalocyanine solution wherein a phthalocyanine starting material is dissolved in a solvent. The phthalocyanine is wherein having high heat resistance, the decomposition temperature of the separated phthalocyanine being at least 10 C. higher than the decomposition temperature of the phthalocyanine starting material. Also, the phthalocyanine solution may be the result of dissolving at least two types of phthalocyanine starting material in the solvent, the separated phthalocyanine being wherein containing a solid solvent of the at least two types of phthalocyanine starting material and by the decomposition temperature of the separated phthalocyanine being at least 10 C. higher than the decomposition temperature of a mixture of at least two types of phthalocyanine separated by mixing the phthalocyanine separation solvent and each of at least two types of phthalocyanine solution resulting from dissolving each of the at least two types of phthalocyanine starting material in a solvent.

The present disclosure is directed to compositions, kits, and methods for synthesizing a Schiff's reagent in situ, i.e., directly on a substrate, such as within a puddle disposed on the surface of a substrate. In some embodiments, the kits comprise at least a dye composition and a sulfite composition. In some embodiments, the dye composition comprises a compound having a 4-Benzhydrylidene-2,5-cyclohexadien-1-imine core functionalized to include at least two substituted or unsubstituted amine groups, wherein the compound has a molecular weight ranging from between about 300 g/mol to about 600 g/mol. In some embodiments, the dye composition optionally includes an acid. In some embodiments, the sulfite composition comprises a sulfite or SO.sub.2 source.

The present disclosure provides stabilized hematoxylin formulations having a pH of less than 2.4. In general, the stabilized hematoxylin formulations comprise a solvent, a hematoxylin dye, and an acid. The present disclosure also provides methods of using such stabilized hematoxylin formulations to stain biological samples. The present disclosure also provides for methods of readjusting the pH of a stabilized hematoxylin formulation to provide a hematoxylin staining solution.

The present disclosure provides stabilized hematoxylin formulations having a pH of less than 2.4. The present disclosure also provides methods of using such stabilized hematoxylin formulations to stain biological samples.

The present invention provides a food colouring composition, in particular the invention provides a composition or colouring composition comprising at least one Polyketide pigment (i) and one or more of the following compounds (ii) a carotenoid (such as lycopene, bixin and/or norbixin), rosmarinic acid, a chlorogenic acid, rutin glucoside, (gamma) cyclodextrin and/or a tocopherol.