A couple of months ago I accidentally created an effect with some curves and color in p5.js. I really liked the effect so I decided to begin plotting and painting the curves.
Note: You can check out this video if you want to see the process in action.
The images below show a couple of pictures of the original curves exported from p5.js. The first curves were just lines. The idea to paint them with watercolor came after I added some low alpha color. They’re organic looking (flower or plant like), fairly simple, and I really dig them. Incidentally, I’ve been thinking about modifying a variation of the curves to put on t-shirts.
Hard Edge Watercolor Painting
Hard edge watercolor painting is trickier than hard edge acrylic painting because the shapes have a tendency to run together. I do my best to paint up to the black line from the pen plot, but sometimes I miss or the water does what it wants. However, “imperfection” is what makes watercolor an appealing medium. I don’t have total control with watercolor and frequently end up with results that are much better than I would have imagined. In that sense watercolor and generative art have quite a bit in common.
For the initial experiment I decided on 4 smaller plots. I expected to get four 4.5″x6″ plots from a piece of 9×12″ watercolor paper. However, the cutting mat I chose to use in the Cameo is short and it overfed in the machine leading to some drift in the images. In the end, it resulted in 2 images that were a little shorter than 6″ and two that were a little longer.
After painting the first set of 4 plots I wanted to plot and paint some additional, larger images. The initial shapes left quite a bit of white space on the paper and I wanted color to fill more of the page. I revised the scripts and adjusted the code to make the shapes take up more room on the canvas.
The images below show some of the paintings from the second run. I also updated the random seed in p5.js to generate new shapes.


The second run turned out better until I decided that I should mat and frame one of the images. I put a mat on the plot and realized that I had two issues: the picture extended behind the mat borders and my paper was a bit wavier than I wanted.
Solving the size issue was relatively easy. I knew I could plot the images smaller. Keeping my watercolor paper flat has been more of a challenge and that’s a discussion for another time. I’ve only been painting with watercolor for a couple of years and I’m still learning what works and that typically comes about by finding what doesn’t work.
Using hard edges forces you to think about how colors look together and side by side. They also cause you to think about composition and how placing different colors in different places changes the curves. The paintings have been really fun and I’m definitely learning as I go.

Hi, I’m Dan.
That’s quite a dynamic, to attempt a “hard edge” work with a medium that such little respect for staying where you want it to. In my opinion, you did a great job making this work!
Thanks Jayson! Yeah, it’s sort of unnatural to try to keep the lines and sometimes the water bleeds over. Initially I wasn’t sure how I felt about that, but I’ve decided that it’s just how the paint wants to go down. They’re fun to paint.