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. You paint on the mask with black to hide, white to show, and gray to make things partially see-through. The original image stays intact — you can always change your mind and paint the mask differently.

You use layer masks when you want to blend two images together, erase part of a photo without losing the original, create a fade effect, or combine multiple photos into one composite. Unlike using the eraser tool (which permanently removes pixels), a mask is non-destructive. You can adjust it, remove it entirely, or paint over it as many times as you want.

The mask sits between your layer and what appears on screen. Photoshop reads it like instructions: white areas say "show the layer," black areas say "hide the layer," and everything in between creates transparency. This separation means your actual image layer never changes.

Key Takeaways

  • Add a layer mask by right-clicking a layer and selecting "Add Layer Mask," then choose whether to start with white (show everything) or black (hide everything).
  • Paint on the mask with black to hide parts of the layer and white to reveal them again — the image itself never gets deleted.
  • Use the Brush tool with soft edges to create smooth transitions and blends between layers.
  • Adjust mask opacity and feathering to control how gradually hidden areas fade in or out.
  • You can view the mask itself by Alt-clicking (Windows) or Option-clicking (Mac) the mask thumbnail in the Layers panel to troubleshoot what you painted.

Adding a layer mask to an existing layer

Start with the layer you want to mask selected in the Layers panel on the right side of your screen. Right-click directly on the layer thumbnail (the small preview image) and choose "Add Layer Mask" from the menu that appears.

A dialog box opens asking how you want to start. Select "White (Full Opacity)" to begin with the entire layer visible, then paint black to hide parts. Select "Black (Full Opacity)" to start with the layer completely hidden, then paint white to reveal parts. For most work, start with white — it's easier to hide what you don't want than to guess what you do.

After you click OK, a white rectangle appears next to your layer thumbnail in the Layers panel. That white rectangle is your mask. Photoshop automatically selects it (you'll see a white border around it), which means anything you paint now affects the mask, not the image itself.

Painting on the mask with the Brush tool

Make sure your foreground color is set correctly before you start painting. Black hides, white reveals. If you need to switch between them quickly, press X on your keyboard to swap foreground and background colors.

Select the Brush tool from the toolbox on the left (or press B). In the tool options at the top, set your brush size and hardness. A soft brush (low hardness value, around 0–30%) creates smooth, gradual transitions. A hard brush (high hardness, 80–100%) creates sharp edges. For blending two images together, soft is almost always better.

Paint directly on your image. Where you paint black, the layer disappears and you see what's underneath. Where you paint white, the layer reappears. Paint slowly and in layers — it's easier to paint again if you need more coverage than to undo a heavy stroke. Adjust your brush opacity (in the tool options) to 50–70% if you want semi-transparent results instead of completely hiding or showing the layer.

Fixing mistakes and adjusting the mask

If you paint the wrong area, just paint over it with the opposite color. Painted black by accident? Paint white over it. There's no undo penalty — the mask is just grayscale information, not pixels.

To adjust how gradually the mask fades, use the Feather option. Select the mask (click its thumbnail in the Layers panel) and go to Select menu → Modify → Feather. Enter a pixel value — 10 to 30 pixels creates a soft fade, 50+ pixels creates a very gradual transition. This softens the edges of whatever you painted.

You can also adjust the mask's overall opacity. In the Layers panel, look for the "Opacity" slider at the top right. This controls how much the mask effect shows. Lower opacity means the hidden areas become partially visible again. This is useful for creating subtle blends or making a masked layer semi-transparent.

Viewing and editing the mask itself

Sometimes you need to see exactly what you painted on the mask, separate from the image. Alt-click (Windows) or Option-click (Mac) the mask thumbnail in the Layers panel. Your canvas now shows the mask as a grayscale image — white areas are fully visible, black areas are fully hidden, and gray areas are partially transparent.

You can paint on the mask while viewing it this way, which makes it easier to see exactly where your strokes land. When you're done, Alt-click or Option-click the mask thumbnail again to return to normal view and see the result on your image.

If you want to see both the image and the mask at the same time, Shift-click the mask thumbnail. A red outline appears around it, and your canvas shows the image with a red overlay where the mask is hiding things. This helps you see which parts are masked without switching views.

Removing or disabling a mask

To temporarily turn off the mask without deleting it, right-click the mask thumbnail and select "Disable Layer Mask." The mask still exists, but Photoshop ignores it and shows the entire layer. Right-click again and select "Enable Layer Mask" to turn it back on.

To permanently remove the mask and keep all the changes it made, right-click the mask thumbnail and select "explore Layer Mask." Photoshop converts the mask into actual transparency on the layer — any areas the mask was hiding become permanently transparent, and you can no longer edit the mask.

To delete the mask and restore the layer to its original state (undoing all the hiding), right-click the mask thumbnail and select "Delete Layer Mask." Choose "Discard" when prompted. The layer returns to full visibility with no mask.

Common uses for layer masks in real projects

To blend two photos together, place them on separate layers, add a white mask to the top layer, then paint black on the mask where you want the bottom layer to show through. Use a soft brush and low opacity for smooth transitions.

To create a vignette (darkened edges), add a black mask to a new dark layer, then paint white in the center with a soft brush to reveal the darkness only around the edges. To fade an image into transparency, add a white mask and paint black from one edge inward with a large soft brush.

To isolate an object from its background without permanently erasing the background, add a black mask to the layer and paint white only on the object you want to keep. The background is hidden but still there if you need it later.

Frequently Asked Questions

Can I copy a mask from one layer to another?

Yes. Right-click the mask thumbnail and select "Copy Layer Mask." Then right-click the destination layer and select "Paste Layer Mask." The mask copies exactly as it was. You can also Alt-drag (Windows) or Option-drag (Mac) the mask thumbnail to another layer to copy it.

What's the difference between a layer mask and a clipping mask?

A layer mask hides parts of a single layer by painting on it. A clipping mask uses the shape or transparency of one layer to control what shows in the layer above it. Layer masks are more flexible for blending; clipping masks are better for constraining one layer's content to match another layer's shape.

Why does my mask look inverted?

Check your foreground color. If black is your background color instead of foreground, you're painting the opposite of what you intend. Press X to swap them. You can also invert the entire mask by selecting it and going to Image menu → Adjustments → Invert.

Can I use a layer mask with text or shape layers?

Yes. Right-click any layer type and add a mask the same way. Text and shape layers work with masks just like image layers do. The mask hides or reveals the text or shape without affecting the layer itself.

How do I make a mask affect only part of a layer?

Create a selection first (using the Rectangle Select, Lasso, or any selection tool), then add the layer mask. Photoshop creates a mask that's white inside your selection and black outside it. You can then paint on the mask to refine it further.