It is soluble, but it depends on what liquid you are talking about. Some are soluble in water, others in alcohol.
Biro ink and chlorophyll are soluble in methylated spirits
there is a product called GLACIERWASH
It is entirely dependent upon solubility. First, the individual dyes that make up the ink's final color must be soluble. Then, the dyes that are more soluble are able to stay dissolved in the water longer than those that are less soluble, therefore getting further up the paper.
Try a paper towel moistened with rubbing alcohol; many inks are soluble in alcohol.
Rubbing alcohol works as a solvent on ink stains because it has polar molecule. Ink also has polar molecule so the like items dissolve each other.
soluble ink is ink that is soluble
Biro ink and chlorophyll are soluble in methylated spirits
Sand is not soluble in ink.
Both the pen and the ink are usually not water soluble
A soluble substance is a substance that can dissolve in another substance.
Chromatography
there is a product called GLACIERWASH
Most office and art supply stores sell this ink. One brand you could look for is India ink.
Are you asking why ink spreads and paper doesn't when water is spilled on a page? Ink is water soluble so it dissolves and spreads. Paper is not water soluble (although it will get soggy) so it doesn't dissolve.
It is entirely dependent upon solubility. First, the individual dyes that make up the ink's final color must be soluble. Then, the dyes that are more soluble are able to stay dissolved in the water longer than those that are less soluble, therefore getting further up the paper.
Try a paper towel moistened with rubbing alcohol; many inks are soluble in alcohol.
Rubbing alcohol works as a solvent on ink stains because it has polar molecule. Ink also has polar molecule so the like items dissolve each other.