Dendrite art | Solar Graffiti

This has nothing to do with solar graffiti. It’s just my latest obsession.

To create a dendrite, the easiest way is to buy:

White gouache paint
Blue ink

The ink must be thin: add water if it’s thick. You should thin out the gouache paint with some water too. Spread the paint, pour drops of ink, and there you go.

I’m doing a fair amount of painting, so I’m using housepaint and paint coloring. I buy white semigloss (satinado). Gouache paint makes dendrites easily. For housepaint you need to add the right amount of water: maybe 15%. But that’s the beauty of it. The dendrites change form depending on how much water you add. You can simply put a drop of ink on top of the paint, but then you’re limited to circles. I like to add drops of ink of different colors to the canvas, then pour the housepaint around it. You can make a big puddle of blue, then pour the white paint into it.

You get “inverse dendrites” when the paint is more watery: the furthest edge is smooth, and you get the tree pattern going inward from the white paint, not from the ink.

You only have seconds with the white housepaint. That’s why I more often pour it onto the ink rather than the other way around. However, with more watery paint, you can wait 10 minutes and it will still form dendrites, acting like less watery paint.

A great effect, though, is once you have a dendrite in one color, you have, say, 10 minutes to retouch: add a drop with another color that follows the original dendrite part way.

Just as most of the amazing patterns in nature are formed from the equilibrium of two opposing forces, in dendrites, it’s surface tension versus diffusion. Subtle changes to this equilibrium will cause a big variety of effects. I don’t try to control the effects too much. Better to let nature create the picture. An interesting effect is that two different dendrites hate to touch each other.

Because of surface tension, water likes to hold together. If after pouring the white paint, I spray a bit of water, then the ink will spread to those small drops, forming more random dendrites.

Here I mixed the white paint with pouring medium to thin it, instead of water. The dendrites were more feathery.

Salt crystal dendrites that formed after mixing salt, water, and papier-mache powder:

Another way to create a dendrite is to put paint between two smooth surfaces, then pull it apart:

With this technique, I created dendrites within dendrites:

The following is close to what I was originally after, to have a painting reproduce natural flow. I’ve noticed that if you see the dendrite forming fast (meaning the underlying paint is too thin), then the dendrite will soon be gone. The dendrite has to form real slowly to hold its form. The dendrites in this painting happened fast, but somehow they held. As with all my best paintings, I haven’t been able to reproduce this. I know it was a big puddle of gray. I poured in some rubbing alcohol too (which pushes the water/ink away). Then 10 minutes later, I poured in a whole lot of blobs of white paint.

Complete dendrite paintings:

While I love going to modern art museums, the beauty of the patterns that appear in nature stun me more than any artist could: a cave of stalactites, river deltas, sand dunes, sunsets, the view from a plane, a giant banyan tree. As a kid, I had a mineral collection, with crystals, a dendrite, and a 3-dimensional copper dendrite.

As an adult shopper in the supermarket, romanescos, pomegranates, and red cabbage call out to me. They always end up in my cart.

As an artist, I want to replicate the patterns of nature, not by imitating them with a paintbrush, but by creating the conditions for the nature to create that pattern on the canvas. (I don’t touch the canvas directly, though I make decisions when I pour liquids.) I’m starting with water. Wind helps, but it’s water that’s responsible for sculpting most of the beauty of the inorganic world: the clouds, canyons, caves, and coastlines.

Dendrites in water seepage result from the equilibrium between surface tension and diffusion. This interplay results in the process called “tip splitting”, the basis for tree patterns.

With trees and water seepage, the pattern is formed from the trunk to the twigs. It’s amazing that when the pattern is created in the opposite direction, from “twig to trunk” as in the following photo of a river basin, the pattern is virtually identical.

Simple rules in nature can produce complex results. It’s simple to program a fractal generator, but a small change to one variable gives a vastly different result. When you play with dendrites, it’s clear that slight variations in the conditions can cause a vast variety of results. The theme behind Ian Stewart’s book, The Beauty of Numbers in Nature, is to answer how snowflakes form. On the last page, he shows how slightly different conditions can cause needles, hollow prisms, sector plates, or the familiar 6-sided dendritic star.

He also looks into how the organic world has evolved to harness chemistry in similar ways, how chemical equilibriums can result in forming a zebra’s stripes. The olive shell’s patterns are produced on the rim of the shell as it grows by a chemical process involving short-range attractors and long-range inhibitors, a similar type of equilibrium between two opposing forces that creates dendrites.

Lightening is another type of dendrite. Has anyone managed to reproduce the lightening pattern in art?

You can also create dendrites from electricity. Check out “Lichtenburg Figures”: if you brush baking soda and water onto wood, then jolt the wood with electricity, you can burn dendrites into the wood.

The following photo is a fulgurite: the underground dendrite pattern made of fused sand or soil that can form when lightening strikes the ground.