Shades of grey to shades of a colour.

[DD]

Greeting from sunny Penzance,

Is there a way to change shades of grey into shades of a colour?

I’ve been experimenting with the commands “Select colours to enhance” and “Photo hue” and have managed to change orange to blue for the selected tool ( see attached ), but this method doesn’t seem to work for shades of grey ?

I guess because grey is not a “colour” ?

I would like black to remain unchanged and white to be fully saturated red and in-between shades of grey to become in-between shades of pink.

I also looked at transparency modes but couldn't see a solution.