I've been wanting a studio assistant for a long time! This particular one doesn't do much, but she can manage to hold onto my wonderful TWSBI ROC 100, which is more than I can do sometimes. This sketch was done across a two page spread using a 6mm Pilot Parallel with blue ink. I've used this pen often for title lettering, but have never tried sketching with it. It has a very wide, stiff nib, so unless the paper is absolutely, perfectly flat, the pen skips spots. That means it doesn't write evenly in a sketchbook. I thought that might make it interesting for sketching though. The pen is designed to give that very wide 6mm line on one end, and very thin line about 0.3-0.5mm when used on its side. I'm not quite sure yet how I feel about the result, but I think it's worthy of further experimentation. I have these pens in all the other sizes too, which I've found much more useful so far than this 6mm one, yet there's something I really like about the way this pen lays down the lines.
My initial intent was to leave the entire sketch blue, coloring in only the TWSBI pen with red and purple. (It's currently filled with purple ink.) But then I thought adding the red to the cloth all the objects were resting on would give the blue a bit more pop and add another dimension to the sketch. I used Winsor Newton Cadmium Red and Permanent Rose watercolor. It wasn't necessarily a bad idea to do that, but it did completely change the focal point away from my studio assistant holding the pen! So I decided that since I did that, I may as well mix up a little of that Schmincke bottle of gold gouache powder, and color the bottle and a bit on the red beside it. Sometimes it's better to stick with the original plan, and sometimes it's better to let the painting lead you to a different idea. I'm not sure which one this was!