How can we deal with colour changes in our printing inks pigmented with carbon black?
Carbon black is the most effective black pigment but its quality must be checked more thoroughly than that of others. In contrast to pigment of other colours, more or less lightening can occur. The type of carbon black must really be carefully matched to the film former and the other pigments, particularly the white pigment. Firstly, for a specified a amount of carbon black, adequate particle fineness should be ensured.
The particle size should not exceed 0,03 u. Secondly, good dispersibility is a criterion for perfect colour stability of the end product. The nature of the carbon black pigment surface (or more precisely the concentration of carboxy, hydroxy, phenol, quinone or hydroquinone groups) has a noticeable effect. lt forms the starting point for tailoring the film forming substance to the resin type.
This shows it self during dispersion of the carbon black in rapid wetting. The usual frequently occuring flocculation does not occur with high quality carbon black pigments, particularly when used in conjunction with TiO2 white pigments. These pigment types with small particle size and good dispersibility are, however, not cheap.
Colour changes in printing inks pigmented with carbon black
Blog, Updated at: 10:02 PM
