Ink of marking pens

Water resistance of water-based ink

It is possible to have some degree of water resistance even if it is aqueous, though not as oily.
The secret lies in the pigment, and it can be said that the pigment is more water resistant than the dye. Among dyes, direct dyes are relatively good in performance, but they can not express colors vividly, so they are only used mostly in black.
It is common to use well-colored acid dyes for color marking pens with many bright colors. Moreover, it can be said that such markings have little water resistance.