Hue shift, absolute replace, colourise

The mode decides more about how a recolour looks than any tolerance does. On a photographed surface one of them keeps the material and one turns it into paint.

What each mode writes

Hue shift rotates each selected pixel onto the target hue, scales its chroma by one factor and leaves its lightness alone. Absolute replace writes the target colour, varied only by each pixel's lightness relative to the selection's mean. Colourise ignores the sample: every visible pixel keeps its lightness and takes the target's colour.

Flattening, measured

The engine ran each mode, at build time, on the same red paint ramp used in the receipts guide: shadow to highlight, carrying a lightness range and a small chroma variation as photographed paint does. The figures are the chroma spread left across the ramp and the share of its lightness range that survived.

One ramp, three modes, the same target
Mode	Chroma spread after	Lightness range
Hue shift	0.037 (was 0.040)	100% of the original range
Absolute replace	0.024 (was 0.040)	110% of the original range
Colourise	0.033 (was 0.040)	100% of the original range

Absolute replace gives the ramp the target's chroma throughout, which is the flattening the eye reads as paint; hue shift carries the original variation across, scaled. Both keep the lightness here, because absolute replace modulates the target by the ramp's own relative lightness.

Choosing

Anything photographed: hue shift. Flat fills, logos, screenshots and white or grey cloth: absolute replace. A monochrome scan or a deliberate wash of one colour: colourise, or the sepia page for a ramp. When in doubt, compare the two at one-to-one with the split view; the difference is in the texture, not the colour.

Back to the swatches

Every pixel is remapped locally — this page has no server to send to.