This technique uses Levels and a blend mode to control monochrome conversion for a two-tone effect
Before/After
On an image of a portrait, to instantly remove colour press Cmd/Ctrl+Shift+U.
Go to Layer>New Adjustment Layer>Levels. Hit OK in the pop-up box and in the Layers palette changes its blend mode to Color.
To warm up the monochrome image, change Levels from RGB to Red inside its adjustment menu. Boost the midtones slider to the left to around 1.60.
For a subdued green tone, select the Green option and slide the same pointer to around 1.80.
To cool down the mood of an image, select the Blue option and adapt all three sliders under the Levels adjustment to adapt the tone.
This is just one way blend modes can be used with adjustments. Check out our Feature in issue 94 (on sale 15 November!) for more creative uses of blend modes in your images, available from Imagine Shop and GreatDigitalMags.com.