I have been preparing some additional Information sheets for forthcoming workshops and classes and attach here a couple of the individual sheets I have prepared .
There is a huge variety of pens that an artist can choose these days, it seems to me that the basic question about a pen is whether it is water-soluble or not? Water solubility is the one aspect that can impact the most as to the look of your work. You may want the ink to run or bloom , or you may be adding a line to emphasise aspects or details of your picture, either would demand a very different pen. Thereafter it is just a question of personal preference as to the feel of the pen along with the thickness of line. My sheet shows the impact different pens can have on your work. Of course there are many alternatives to the one I have shown out on the market.