What a layer mask does and when you need one
A layer mask in Photoshop lets you hide or show parts of a layer without deleting anything. Instead of erasing pixels permanently, you paint black on the mask to hide, white to reveal, and gray to make things partially transparent. The original image stays intact — you can always undo the mask or paint it back in later.
You use layer masks when you want to blend two images together, fade an edge gradually, or remove a background without destroying the original layer. They're especially useful in photo editing when you need to experiment — if you mask something out and change your mind three edits later, you just paint white back onto the mask and it reappears.
Key Takeaways
- Right-click the layer in the Layers panel and choose "Add Layer Mask", then pick "White (Full Opacity)" to start with everything visible.
- Paint with black on the mask to hide parts of the layer, white to reveal them again, and gray to make areas semi-transparent.
- The mask itself is separate from the image — you can edit the mask without changing the actual pixels on the layer.
- Click the layer thumbnail (not the mask) if you need to edit the image itself, or click the mask thumbnail to paint on the mask.
Adding a layer mask to an existing layer
Open your image in Photoshop and locate the layer you want to mask in the Layers panel on the right side of the screen. Click the layer once to select it, then right-click directly on the layer name or thumbnail.
From the menu that appears, select "Add Layer Mask". A dialog box opens with three options: "White (Full Opacity)", "Black (Full Opacity)", and "Clipping Mask". Choose "White (Full Opacity)" unless you have a specific reason to start with the layer hidden — white means the entire layer is visible, and you'll paint black to hide parts of it. Click "Add" and Photoshop creates a white rectangle next to your layer thumbnail in the Layers panel. That white rectangle is your mask.
Painting on the mask to hide and reveal
Once the mask is added, make sure the mask thumbnail (the white rectangle) is selected — it should have a white border around it. If the layer thumbnail has the border instead, click the mask thumbnail to switch to it.
Select the Brush tool from the toolbox on the left, or press B. Set your foreground color to black by pressing D (this resets colors to black foreground and white background). Now paint over the parts of the layer you want to hide. As you paint, those areas fade away, revealing whatever is below — another layer, a background, or transparency.
If you hide too much, switch your foreground color to white by pressing X, and paint over the mask again to bring those areas back. Gray paint makes areas partially transparent, useful for soft edges and gradual fades. Adjust your brush hardness and opacity in the tool options at the top to control how sharp or soft the edges are.
Using the mask with layer blending and effects
Layer masks work alongside other Photoshop features. If you've already applied a layer style (like a drop shadow or stroke), the mask will affect how that style appears — the shadow only shows where the layer itself is visible. If you add an adjustment layer above your masked layer, the adjustment applies to the entire image, including the transparent areas created by the mask.
You can also use the mask with layer blend modes. Change the blend mode in the Layers panel dropdown (where it says "Normal" by default), and the mask still controls which parts of the layer show through. The mask is always independent of the blend mode.
Refining the mask with gradients and selections
Instead of painting freehand, you can create a smoother transition using a gradient on the mask. Select the Gradient tool, make sure black is your foreground color and white is your background, then drag across the mask from the area you want hidden to the area you want visible. This creates a smooth fade rather than a hard edge.
You can also create a mask from a selection. Make a selection using the Rectangle Select tool, Ellipse Select tool, or any other selection method, then add the layer mask. Photoshop automatically converts the selection into a mask — the selected area becomes white (visible) and everything outside becomes black (hidden).
Copying, disabling, and removing masks
To copy a mask from one layer to another, right-click the mask thumbnail and choose "Copy Layer Mask". Then right-click the destination layer and choose "Paste Layer Mask". This is faster than recreating the same mask by hand.
If you want to temporarily hide the mask's effect without deleting it, right-click the mask thumbnail and choose "Disable Layer Mask". The mask stays in the Layers panel but stops affecting the layer. Choose "Enable Layer Mask" to turn it back on. To permanently remove the mask and keep all the layer visible, right-click the mask and choose "Delete Layer Mask".
Frequently Asked Questions
Can I undo changes I made to the mask?
Yes. Use Edit > Undo or press Ctrl+Z (Windows) or Command+Z (Mac) to step back through your mask edits. You can also use the History panel to jump back to any earlier state. The mask itself is never permanent until you flatten the image or export it.
What's the difference between a layer mask and erasing?
Erasing deletes pixels permanently. A layer mask hides pixels without deleting them, so you can always paint white on the mask to bring them back. Masks are non-destructive — the original image data stays on the layer.
Why does my mask look like it's not working?
Check that the mask thumbnail (not the layer thumbnail) has a white border around it in the Layers panel. If the layer thumbnail is selected instead, your brush strokes are painting on the image, not the mask. Click the mask thumbnail to switch.
Can I use a layer mask on a text layer or smart object?
Yes. Right-click any layer type and add a layer mask the same way. For text, the mask hides parts of the text without converting it to pixels. For smart objects, the mask works on the displayed result without affecting the original smart object data.