I chose an Image with a particular vibrant colour standing out, to edit on photoshop. I duplicated the background layer and made this black and white through image>Adjustments>Black and white.

Colour splash.

The new layer is now black and white.

On the colour image, I wanted to select a brightly coloured part of the image. I chose the blue makeup around the eyes. To select this easily I clicked on Select>colour range then changed the fuzziness. This allowed me to select only the blue area of the picture. I then inverted the selection so all the other colours were selected and could be deleted.

With the Black and white layer underneath, I wanted it to stand out more, so I went on Image>adjustments>Brightness/contrast and changed the levels to create more of a noticeable difference between light and dark tones.

The blue layer was looking dull so I went on Image>adjustments>Hue/saturation to make the colour more vibrant, changing the saturation levels.

This is the outcome.