YFilm Chromatic

The chromatic aberration of a real film lens on the GPU: lateral fringes, axial halos and purple fringing, traced across the spectrum.

Glass bends every wavelength by a slightly different amount, so the colours of one image land in different places. YFilm Chromatic traces the spectrum from violet to red and gives each wavelength its own shift, focus and colour, which makes the three effects you see in real footage: lateral fringes that grow towards the corners, axial halos around bright edges, and purple fringing from blown highlights.

Flat and grey areas keep exactly the same colour and brightness; only edges get fringes. Ten looks, from a subtle film lens to a glitch split, set the controls in one click, in Nuke and in After Effects.

  • Lateral CA: samples, strength, separation and edge attraction power, with an inward, outward, linear shift or anamorphic direction.
  • Lens: full spectral (prism) fringes, or red / cyan, purple / green and blue / yellow two-colour fringes, with colour balance, squeeze for anamorphic glass and a movable lens centre.
  • Longitudinal CA: axial blur with purple halos (in front of focus) or green halos (behind focus).
  • Purple fringing: violet bleed from blown-out highlights into the dark side of high-contrast edges, with radius, highlight threshold and fringe colour.
  • Finish: fringe saturation, dither that turns banding into fine noise, views of the fringes alone, the falloff map and the purple fringe mask, and mix.
  • Edge modes: transparency, extend, mirror or repeat past the frame. Premultiplied CG with alpha works, with the alpha shifted along with the colour.
  • Nuke: Nuke 13 or later, BlinkScript. Runs on the GPU (Metal, CUDA or OpenCL) or vectorised on the CPU.
  • After Effects: AE 2022 or later on macOS 11+ (Apple Silicon and Intel). 8, 16 and 32 bpc.
  • Speed: Scales with Samples times axial samples. If a look feels slow on 4K, lower Samples first; dither keeps it smooth.
  • Resolution: Strength and radius are in pixels, so the same values look half as strong on a 4K plate as on HD.

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