The viscosity of the ink strongly depends on the temperature at which it’s printed: in warmer seasons it is more fluid than in colder seasons and so the addition of the same quantity of diluents in both cases may cause different viscosities of the ink. Since the inking is directly proportional to the viscosity (in printing systems with rubber roller mainly) a different charge of ink with the same dilution, may occur.
Even printing with constant viscosity is a good working method, although it’s not always decisive: during winter a high dilution (with resultant high reduction in pigmentation) might be necessary, while during summer a low dilution is used. In order to obtain the best reproducibility in prints it’s necessary to adjust the dilution to achieve/obtain the desired shade.
In the case for inks formulated for printing on paper and cardboard, the constancy of the characteristics of the substrate to be printed (e.g.: absorbency, Havana brown shade, white level…) is very important.
