The Texture group holds five Effect Layers: Diffusion, Grain, Halation, Sharpen, and Vignette. Add them from the Add Layer menu (the plus button at the bottom of the Editing Layers stack), under the Texture heading. Each is a layer in the Image Stack and can be expanded, collapsed, enabled, disabled, reset, duplicated, removed, and reordered. Several of the same type can be stacked.

These layers don’t imitate film frame-for-frame; they borrow the effects film has on how an image feels. Grain and Halation in particular work together to shape perceived sharpness and focus — often more than a sharpening pass does.

Diffusion

A general glow. It scatters light from bright areas into the darker areas around them, the way glass — a lens, or a filter placed over it — spreads light, softening the image and letting highlights bloom into their surroundings. Use it to take the hard edge off a digital capture. Depending on the glass it models, it can add a slight tint.

  • Strength — amount of scatter.
  • Radius — how far the scatter spreads.
  • Hue Shift — R, G, B sliders that tint the scattered light.

Grain

Adds grain. Beyond texture, grain changes how sharp and how focused an image reads; with Halation it is one of the main controls over that perception.

  • Size — grain size.
  • Softness — reduces image sharpness the way larger grain does on film. Bigger grain physically obscures fine detail, so as grain grows the image should lose a little sharpness to match; Softness applies that blur. Inactive while Auto-Soften is on.
  • Auto-Soften — sets Softness from the grain size automatically, using Aphera’s suggested ratios, so the softening tracks the grain without manual tuning.
  • Blend
    • Overall — overall grain strength.
    • Tonal Bias — shifts the grain toward the shadows or the highlights.
  • Texture
    • Grain Color — how much color the grain carries.
    • R, G, B — per-channel grain strength.

Halation

Replicates the reddish fringing film produces around bright lights, where the light bleeds into the emulsion. Where Diffusion is a general glow, Halation is the specific halo around the brightest points in the frame. Used with Grain, it shapes how sharpness and focus are perceived.

  • Strength — amount of fringing.
  • Size — spread of the halo.
  • Sharpness Conservation — preserves edge sharpness against the halo, so the bloom doesn’t read as simply out of focus.
  • Hue Shift — R, G, B sliders that set the tint of the halo; film halation is characteristically reddish.

Sharpen

Raises perceived sharpness by increasing local contrast — the difference between neighboring areas that are otherwise similar. Sharpening doesn’t add detail; it makes existing detail read more clearly.

  • Strength — amount of sharpening.
  • Frequency — the size of detail the sharpening targets. Match it to the scale of texture you want to bring out.
  • Halo Reduction — reduces the bright and dark halos sharpening leaves along high-contrast edges.
  • Grain Overshoot Reduction — keeps sharpening from over-emphasizing grain.

Vignette

Darkens or lightens the image toward its edges, drawing the eye toward the center of the frame.

  • Exposure — how much the vignette darkens or lightens the affected area.
  • Size — extent of the vignette.
  • Softness — falloff at the edge.
  • Style — sets the shape of the vignette:
    • Optical — an oval vignette, like the falloff a camera lens produces. Exposes a Lens Shape slider.
    • Print — a rectangular vignette, like the burned-in edges of a darkroom print. Exposes a Curvature slider.
  • Hue Shift — Temp and Tint sliders that tint the vignette.