Invert Colors in Photoshop Using Shortcuts and Adjustment Layers
Photoshop lets you invert colors in one step or with a non-destructive adjustment layer. You’ll learn the quick keyboard shortcut, how to add an Invert adjustment layer, and how to target specific layers with a clipping mask for precise control.

Step-by-step instructions
Invert quickly with a keyboard shortcut
Select the layer you want to invert in the Layers panel.
Press Ctrl+I (Windows) / Command+I (Mac) to invert colors.
Press the same shortcut again to revert if needed.
Use an Invert adjustment layer for flexibility
Go to Layer → New Adjustment Layer → Invert, then click OK.
All layers below the Invert layer will display inverted colors.
Lower the Invert layer’s Opacity to reduce the effect if desired.
Drag the Invert layer above/below other layers to control what it affects.
Limit the invert effect to one layer
Hold Alt (Windows) / Option (Mac) and click between the Invert layer and the target layer in the Layers panel to create a clipping mask.
The inversion now applies only to that clipped layer.