Best pen for sketching - what is it and how to use? Tips and techniques

You already know that sketching with a pen rather than a pencil, makes you more committed to the line and really sharpens up your observation skills, but which is the best pen to use? You also know that if you have to take the kitchen sink with you, when you go out en plein air, you probably just won't go. That's why I love the Stabilo 88.
Let me introduce you to the pen. Whether in the studio or out and about, it is versatile and does two jobs in one. It gives you line and it gives you wash, but you can add watercolour without it going into a muddy mess. I'll share a few ideas for getting the most out of it... and your sketching will thank you for it!
Available in 50+ colours, I recommend using the black or brown (46 and 45) for sketching and show you a few examples - from 5 minute studies in a zoo, to longer layered sketches.
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