Colour lab
See the third colour before we ink a drum.
Pick two or three inks. Place a shape. Where they cross, the multiply blend invents a colour we did not load. Screens only approximate real ink on paper — fluoro pink, especially, is ruder in the hand than on glass.
Inks on this sheet: Fluoro Pink, Riso Blue, Sunflower. Overlaps darken because the plates multiply. A screen is only a cousin of ink on paper.
The colour lab needs JavaScript to place and move shapes. The sheet above is the starting sketch.