Technique · Geometry
Medusa plate
An engraved page of jellyfish in dark ink on cream: ribbed gourd bells, a ringed top view, club-tipped tentacles and a star, with pink beads on the rims.
Medusa plate is drawn geometry, rebuilt as it changes. 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
- The tentacles of many jellyfish are armed in rings or knobs of stinging cells, called nematocyst batteries, which an illustrator can draw as clubs.
- Ernst Haeckel's plates of medusae in Kunstformen der Natur (1904) present the radial symmetry of jellyfish as a source of designs for architects and craftspeople.
- A jellyfish seen from above shows its radial symmetry: the number of arms or lobes is often four or a multiple of four.
- Carl Linnaeus gave jellyfish the name Medusa in the eighteenth century, after the Gorgon of Greek myth whose hair was snakes; today a medusa is the free-swimming form of a jellyfish, as opposed to its attached polyp stage.
- Ernst Haeckel's plates in Kunstformen der Natur were lithographed from his drawings by Adolf Giltsch, who drew each design onto the lithographic stone.
The mathematics
- Each bell is a surface of revolution: its profile r(t) is turned about the vertical axis, and a rib at azimuth phi is drawn at x = r(t) sin(phi), so a hundred ribs cost one formula.
- Each rib's width is set to 45 percent of the gap to its neighbour, which at the middle of the bell is large and at the edge is small: light and shade built from nothing but line width.
- The club on a tentacle is a chain of capsules whose radius rises and falls as sin(pi u) over the last third of its length, so a spindle is built from a few dozen round-ended segments.
In art
- Engraved plates were made line by line: the engraver's tools cut a groove, and the width and depth of the groove decide how much ink it holds and so how dark the line prints.
- Haeckel's plates fed into Art Nouveau: the architect Rene Binet drew on his radiolarians for the great gateway of the 1900 Paris Exposition.
More ways to use it
Related techniques
L-system · Space colonisation · Diffusion-limited aggregation · Flow ribbons · Ridgelines · Curve families · Streamlines · Paint strokes