Explain the method of separating coloured components from blue/black ink.

Hint: There are various methods for the separation of mixtures, which includes decantation, filtration, crystallization, evaporation, sedimentation, distillation, chromatography etc. Chromatography is a technique used for the separation of components of coloured mixtures.

Complete step by step answer:
We know that most of the natural compounds or substances are chemically not pure. There are various methods for the separation that can be used to obtain individual components from the mixture. By separation, it becomes possible to use and study individual components of the given mixture.
We know that the ink is a colloidal solution and a heterogeneous mixture of dye in water. Therefore, we can separate the volatile solvent from the non-volatile solute using the method of evaporation
There are some simple steps to obtain coloured component (dye) from the blue/black ink is as follows:
Fill the beaker (half) with water.
Place a watch glass over the mouth of the beaker and then add a few drops of ink.
Now, heat the beaker (do not heat the watch glass containing ink directly). You will observe that the evaporation is taking place.
Continue heating the beaker as the evaporation process goes on and then stop heating when there is no further change in the watch glass.
Now, we can conclude that heating leads to the evaporation of water leaving behind the dye in the watch glass. Hence, by the method of evaporation we can separate coloured components from blue/black ink.

Note:
We need to memorize that paper chromatography can also be used for the separation of coloured components in the mixtures such as dye, plant dye and food colourings. This method is not effective for quantitative analysis and complex mixtures.