When I have sketched, I have mostly used either pencil or pen with water-soluble ink. The result has been that I have not been able to combine color with line. The other day I pulled my father's technical pen set out of a drawer. I would guess conservatively that the set is 30 years old. I suspect it is older than that. It is a Castell TG technical pen set, and contains 9 pens with nibs of different sizes - largely unused. How would they work? I bought some Rapidograph waterproof ink for $5 and filled a pen with a size 2.5 nib. The ink flowed very smoothly.
So at my in-law's house I drew a straggly plant in an interesting pot. I was not so careful as I usually am. So what if the drawing were to be a bit skewed? This was just an experiment. Then I brushed on the watercolor. Color and line - something new (for me) - and it worked just fine.
Well, my mother-in-law liked the drawing so much that she wanted to keep it. It became a part of her mother's day gift and this small 4" x 6" drawing is now hanging in her house, warts-and-all, next to the plant itself. So maybe you'll like it too, as imprecise as it is. It also happens to satisfy Everyday Matters challenge #136 - "Draw or paint something that's alive - a living thing - animal or plant." And this plant, though straggly, qualifies as alive.
3 years ago