Question 1

How do I make colours pop in a photo?

Accepted Answer

Raise saturation a little — around +20 to +40 is usually enough. Beyond that skin tones go orange and reds lose all their internal detail.

Question 2

How do I remove all colour?

Accepted Answer

Drag saturation to −100. That is equivalent to greyscale, though the dedicated black-and-white tool uses perceptual luma weighting and gives a slightly more natural result.

Adjust image saturation