Measurements show that all three royal-blue inks have very similar viscosities of about 1.01–1.03 mm²/s — only some 10 percent above water, with no real difference between them. There is, however, a clear difference in surface tension: Montblanc is around 49 mN/m, Pelikan around 57 mN/m and Lamy around 69 mN/m, so Montblanc shows the easiest start-up behaviour. A further drop in surface tension would lead to uncontrolled ink flow. Viscosity is determined with a capillary viscometer at a temperature held constant to 0.01 °C; surface tension is measured by the Wilhelmy method using a platinum ring or plate and a high-precision balance. Personal experiments with other inks can be useful, since the nib's behaviour and the ink interact strongly.