In the beginning when working with ink I drew exclusively with quill, because I intended for a long time to outline comics with ink. (Reason: A quill leaves a much more lively line than fineliner... but ink can smear much easier...) Anyway I din't come far with it, at least I didn't come to clean, exact outlines. Now, I use ink most of the time for pictures that don't need to be especially exact or are intended to be "unclean".
Some time ago I begun to use ink in conjunction with a brush, inspired by Japanese caligraphy and painting. Through thinning with water an incredibly large spectrum of lively grays is revealed. A part from that I can work much more generously with brush than with quill! That's how I got away a bit more from the standard A4 sheet... adding the idea with the sprinkels... very risky, because they land randomly, on the other hand interesting and impressive, if the drops land at the "right" spot.
I wasted a thought or two on red ink, but have only ever used it in conjunction with black. Let's see what happens... ;-)

brush
quill, quill and brush

brush: page top brush, quill and brush: page top copyright © by Nadia Bader