Digital ink and paint is the process by which scanned hand-drawn line art is coloured and composited on computer, eliminating the physical cel from the production pipeline. Japanese anime adopted the technique through the late 1990s; by the early 2000s most TV anime was produced digitally, with traditional cels surviving only in specific theatrical productions.
Pipeline outline
In a typical digital pipeline, animators continue to draw on paper. Drawings are then scanned, the line art is cleaned up, and colour is filled inside the line work using software such as Celsys RETAS or Toon Boom Harmony. Backgrounds (still often painted, sometimes digitally) are composited with the coloured line work in dedicated compositing software, traditionally Adobe After Effects.
Industry adoption
Toei Animation produced the first fully digitally-coloured Japanese TV anime episodes in the late 1990s. By 2003 nearly all new TV anime was digital. The transition reduced per-shot cost (no more physical acetate, no more photography of cels) and enabled compositing techniques — lens flares, gradient overlays, depth-of-field — that had been impractical with physical cels.
Effects on style
The shift produced a slow visual change. Colours became more saturated; gradients and effects more elaborate; lens flares more common (one of Makoto Shinkai's signatures, technically trivial in digital compositing). Some traditionalists — including parts of Studio Ghibli — preserved hand-painted backgrounds and resisted the heaviest digital effects.