Pen & Brush Doodles
A quick drawing with Diamine Ancient Copper and Diamine Midnight to illustrate how fountain pen ink behaves when diluted with water. The colours love to mix and create interesting patterns. A bit of their vibrancy is lost when dried but there's still a fair amount of colour left.
|Quick sketch with fountain pen ink and water|
Also the colours don't become permanent like watercolour so they're harder to layer. Still, to sketch, then use a bit of water and bam! Clouds of colour exploding, that's really neat.
There are watercolour pencils and even ink pencils which are designed for a similar purpose but can't quite deliver the same effect. They have other advantages however, like easier layering.
Here's fountain pen ink next to a Faber-Castell ArtGrip watercolour pencil and a Derwent Inktense ink pencil. I tried to put roughly the same amount of pigment on the paper with the two pencils, even taking the lighter colour into account the watercolour pencil is very pale when washed over with water, the Inktense pencil releases its pigments somewhat more readily but in this respect they're both absolutely no match for the fountain pen ink. It seems like you could do a light wash over half the page with the amount of colour provided by that tiny doodle.