Technique · Fields
Rainbow strata
A landscape of thin layers lit like cut paper, felted wool or impasto, in colours that slide along each layer.
Rainbow strata is a field drawn for every pixel by the graphics chip. Every piece on Synapse Drip is made from a recipe that layers techniques like this one, and you can change any of it in the Studio.
Good to know
- Paper relief models of landscapes are built the way these layers are: one sheet cut per contour, then stacked, so flat card becomes terrain you can hold.
- Wool dyed in a few strong colours and felted together makes soft, banded surfaces; felt artists can cut and stack layers just as a paper artist would.
- Sedimentary rock shows its layers because different seasons or ages laid down different grains, and a fold in the strata, like the ones here, shows where the ground was squeezed.
- In 1669 Nicolaus Steno proposed that in undisturbed rock the lowest layers are the oldest, the law of superposition that lets geologists read a cliff as a calendar.
- In 1778 Charles Hutton worked out the density of the Earth from how much a Scottish mountain, Schiehallion, pulled a plumb line sideways; to find the mountain's volume he drew lines of equal height across it, an early use of contour lines.
- Felt is made without weaving: wool fibres have tiny scales, and heat, moisture and pressure lock them together.
The mathematics
- The field h is cut at 66 evenly spaced levels with floor(h x n) and fract(h x n); the screen distance to the nearest step is fract / |grad|, so the layers narrow where the ground is steep and widen where it is flat.
- Contours of a single smooth function can never cross, because a point has only one height: that is why the ribbons nest and bend round one another instead of tangling.
- The lit rim of a step is decided by one dot product, between the direction the step faces (the negative gradient) and the direction of the light.
- The colour field is a second, independent noise, so the hue changes along a layer while the layer's own height stays constant.
In art
- Morris Louis poured thinned acrylic down tilted canvases in the 1950s and early 1960s, leaving bands of saturated colour that flow and overlap like these.
- Impasto lets paint cast its own shadow; thick, layered paint looks carved because every ridge catches light on one side.
More ways to use it
Related techniques
Nebula and stars · Liquid · Droplets · Network · Terrain and maps · Neuron · Order to chaos · Fractal tree