These are bottles of ink I've received from Renesans, an art supplies manufacturer from Poland, during the Urban Sketchers Symposium in Amsterdam a few months ago.
There's Indian Ink, acrylic Ink and black ink with shellac. When I choose black inks, I only care whether they are waterproof or not since I use watercolour over ink, and whether they can be used in fountain pens since I use those pens often. So what are the differences between acrylic ink and India ink? Is one better than the other? Better in what sense?
Acrylic ink is made with pigments suspended in acrylic resin binder or polymer emulsion.
Acrylic ink is more fluid and flows better. Think of it as the more fluid version of acrylic paint, and it can come in many colours. It can be used with dip pens, brushes, airbrushes, markers and stamps. It's waterproof but can be lifted off with alcohol so you don't use these with alcohol markers.
India ink is made with carbon or lamp black pigment (I'm referring to black ink) mixed with water, but sometimes with varnish, gelatin or varnish is added to make the ink more durable or waterproof when dry.
India ink may or may not waterproof. They can be used with dip pens and brushes. They are also available in different colours, such as those available from Dr Ph Martin's.
There are certain things to test for when using such inks. Whether they are waterproof, are they matte when dry and how fast do they dry.
The ink needs to be waterproof if you use water media, such as watercolour. Some inks will dry with a sheen and that may affect the look you expect. Fast drying inks can be difficult to use with brush as the brush hair will become solid and when ink solidifies it's difficult to wash off completely.
These are the sketches I drew with the three inks.
This was drawn with the acrylic ink.
It looks quite matte.
This was with the Indian ink which is Sepia coloured.
This with the shellac ink.
The shellac ink has sheen at areas where the ink is concentrated.
The acrylic ink is completely waterproof. I sprayed this with a mist bottle and the water collected into droplets.
This bottle of Indian ink from Renesans is very water resistant. I do see some parts that were soluble.
But for the most part it's waterproof.
The shellac ink is a surprise because it's not waterproof. Shellac is supposed to form a protective coat over the ink to make it waterproof but for some reason it doesn't work here. Yes, I did shake the bottle, well, I shook all three.
All the inks can be thinned with water.
If you want to use such inks with dip pens or brushes, it's better to get bottles that have a large opening unlike the tapered opening here.
And make sure to clean your dip pens and brushes immediately after use so that the ink doesn't form a thin coat which will make it difficult to clean and for the ink to flow for subsequent use.
Ultimately, regardless of the ink you use, always test them first.
To sum up this post. Acrylic is waterproof but don't use it with alcohol markers. India inks may or may not be waterproof. Both types of inks are very lightfast and suitable for use on artworks that require permanence.