[Tutorial] Creating a duotone effect

[Andrius]

The duotone effect is a very striking and colorful effect inspired by a popular printmaking technique. The effect is achieved by recreating an image using just two colors — one for the dark parts of the image and one for the light ones. This usually emphasizes the midtones and highlights, drawing attention to the subjects in a photo. And the best part? Creating this effect couldn’t be simpler.
Read the full tutorial.

[auludag]

At the end it says "Simply choose the Color Adjustments tool and apply the Black & White adjustment to the same image."

There is no such Black & White selection in that.

[Andrius]

Here's what I'm seeing when I choose the Color Adjustments tool and click the Add button:

Another way to add the adjustment is by choosing Format > Color Adjustments > Black & White (from the Format menu at the top of your screen).

[Tom May]

Good stuff. BUT: Why is there no tritone or quadtone? These are some of my favourite effects and I really wonder why I can't add additional colours. The third colour simply gives it a little extra spice. Please add that feature. It's been in Photoshop forever. Affinity Photo has the gradient map effect, which can do all that.
BTW: For the old Pixelmator app (without the "Pro") I could download plugins that would do that, albeit not as nicely as in Photoshop/Affinity.

[Andrius]

There's no specific reason as to why this doesn't exist, we simply haven't created a feature like this yet. But we like the effect too, so we'll keep this in mind!