reducing an image to a single colour

[skydad]

without printing, how can i digitally reduce my images to a single colour like this?

i see this style a lot, but am completely clueless about the technique.
id love to know more about it, or simply if it has a name.

any advice is appreciated

 

[Paul Murray]

A number of ways. The way I do it in Photoshop is Image > Adjustements > Gradient Map then set the colours (make sure one is white).

 

[skydad]

holy shit that was simple

life changed, thank you