BYTETOOLS

Colour Splash Effect

Keep one colour and turn everything else black and white. Pick the hue by clicking the photo, then tune the tolerance and feather band.

Drop a photo to grey out everything except one colourProcessed locally in your browser — never uploaded

What is the Colour Splash Effect?

The colour splash — a red dress in a grey street, one yellow taxi in a monochrome city — works by keeping pixels whose hue is close to a chosen colour and replacing everything else with its brightness.

  • Click-to-sample the keep colour straight from the photo
  • Circular hue matching with an adjustable tolerance and a feathered edge band
  • Minimum-saturation and lightness limits to exclude greys and highlights
  • Choice of Rec.709 or Rec.601 luma for the greyscale conversion
  • Invert switch to grey out just the chosen colour instead
  • Live percentage readout of how much of the frame stays in colour

How to use the Colour Splash Effect

  1. 1

    Drop in the photo, then click the colour you want to keep directly on the original.

  2. 2

    Fine-tune with the hue slider, hex box or preset list if the sampled colour is slightly off.

  3. 3

    Raise the hue tolerance until the whole subject is included, and set the feather band to soften the edge of the selection.

  4. 4

    Use the minimum saturation and lightness limits to keep pale greys and blown highlights out of the selection.

  5. 5

    Optionally tick Invert to grey out the chosen colour instead, then click Download PNG.

About the Colour Splash Effect

The colour splash — a red dress in a grey street, one yellow taxi in a monochrome city — works by keeping pixels whose hue is close to a chosen colour and replacing everything else with its brightness. This tool does exactly that, measuring each pixel's hue distance around the colour wheel and fading smoothly across a feather band so the selection has no hard jagged edge.

Click anywhere on the original to sample the colour you want to keep, or set it with the colour picker, a hex code, a preset hue or the hue slider. Tolerance sets how far around the wheel still counts as a match, and separate saturation and lightness limits stop washed-out greys and blown highlights from sneaking into the selection.

Grey is computed with your choice of the Rec.709 or Rec.601 luma formula, and an invert switch flips the whole thing so the chosen colour is the only thing that turns grey. All of it runs locally in your browser — the photo is never uploaded.

Frequently asked questions

What is a colour splash photo?

It is a black-and-white photo with one colour left intact — a red umbrella, a blue door, a yellow cab. The effect draws the eye straight to the coloured subject, which is why it is used so often in posters and adverts.

Why is part of my subject still turning grey?

Shadows and highlights on a coloured object shift its hue and drop its saturation, so parts of it fall outside the selection. Raise the hue tolerance, then lower the minimum saturation until the darker and paler areas come back into colour.

Why are red and orange objects both being kept?

Hue is a circle and red sits at 0° with orange only about 30° away, so a generous tolerance catches both. Reduce the tolerance and use a narrow feather band to separate them, and check the percentage readout to see how much of the frame is being kept.

What does the feather band do?

It sets how many degrees of hue the selection takes to fade from fully coloured to fully grey. Without it the boundary is a hard cut that shows as a jagged outline; a feather of 10 to 20 degrees usually looks natural.

Does the greyscale formula actually matter?

It changes how bright each colour looks once desaturated. Rec.709 weights green heavily and matches modern displays, while Rec.601 lifts reds slightly; on most photos the difference is subtle but visible in strongly coloured areas.

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