In this START 3TM (Tips & Tricks' Two Minutes) post/video, you will learn how to create a duotone effect in Adobe Photoshop.
Fortunately, it doesn't need more than two minutes, and a creative mind to create a wonderful artwork 😁
1- Prepare your image
Go to the Image menu, choose Adjustments then click on Hue/Saturation. Or you can take a shortcut by clicking cmd+u (on Mac) or ctrl+u (PC)
Decrease the Saturation to (-100).
2- Add a Gradient Map
In the Layers tab, click on create an adjustment layer.
Click on Gradient Map.
Click on the colors on the Properties tap.
Now change colors to fit your design.
Or you can download the Gradient Preset from here