I've found this pic from a year ago. It was a birthday gift for my friend Setka airbrush master. To create this I used a broad edge poster nib shown below.
This is a very good nib for ink work. If you want to create nice looking letters that have this particle of handmade work this is a good choice. It works amazing with talens ecoline (below).
This nib works fine on watercolor paper. To create this nice looking color merge just use one (lighter) color first to create the design and add the darker color while previous is still wet. In one of my old Youtube videos I have shown a way to create a different cool effect by writing with water and than adding ink drops to it...
Have fun !