Engine stage: ink

Modal

Parameter	Default	Range	What it does
ink_amount	0	0 – 1	How far the frame is remapped onto the paper-and-ink pair; 0 leaves it untouched.
paper_hue	0	0 – 1	Hue of the colour an unlit pixel becomes, as a position around the wheel.
paper_sat	0	0 – 1	Saturation of the paper colour; 0 is neutral.
paper_bright	1	0 – 1	Brightness of the paper colour, which sets how light the empty ground reads.
ink_hue	0	0 – 1	Hue of the colour a fully lit pixel becomes.
ink_sat	0	0 – 1	Saturation of the ink colour; 0 is neutral.
ink_bright	0	0 – 1	Brightness of the ink colour, which sets how dark the drawn marks read.
ink_gamma	1	0.25 – 4	Shapes the paper-to-ink ramp: below 1 the mid tones bite earlier, above 1 they hold back.

Unbound parameters fall back to the defaults above. An unknown parameter name is reported as a load-time warning naming the param and the system — the preset still loads and its other bindings apply.

Several names appear under more than one system and mean the same thing wherever they do: the shared view transform (zoom, pan_x, pan_y) and the line-mirror controls are discussed under Engine-wide controls, and the palette group (saturation, palette_mix, palette_steps, palette_contour, and hue where a scene has one) under Colour — the palette surface. Their defaults differ per system where the table says so, and their meaning does not. Every system additionally accepts the engine-stage params bg_*, trails, kaleido_*, bloom_*, occlude, exposure, and the final ink_*/paper_* remap documented there.

The attractor roster is the one place a param’s meaning depends on the family. a b c d mean different things per family and mean nothing on the five IFS figures; morph curl vigor lean bias and map_tint map_hue root_tint root_hue emergence are IFS-only and are inert on the four map families; perspective depth_fade depth_hue reach only the two 3-D flows. Binding an inert one is not an error and produces no warning — it produces nothing at all. See The five IFS figures, What made this point, and how far into the figure it is and Attractor depth.

My attractor is too bright / too dim — which knob? brightness. It is a plain multiplier on the light each particle deposits (default 1.0), so it changes the figure’s level and nothing else: same points, same trail, same geometry. It is the same param, under the same name, that swarm and emitter carry (ADR-0080). The deposit is already normalized by particle count, so brightness composes with [particles] density rather than fighting it. Not exposure — that is the whole-frame stop, it crossfades as a scalar across a preset dissolve, and bloom_threshold is measured against it; see Linear light and exposure. size and fade also move the level, but they move the picture with it — a wider nib and a longer trail — so use them when that is what you want.