Method 1: Using an Existing Square Shape

How to Mask a Square in Photoshop

Masking a square in Photoshop is straightforward and can be achieved using several methods. The best approach depends on whether you want to use a pre-existing square or create a new one.

This method works best if you already have a square shape layer in your Photoshop document.

1. Select your layer: Choose the layer containing the image you want to mask.
2. Select your square shape layer: Click on the square shape layer you want to use as a mask.
3. Apply the mask: On macOS, select Object > Mask with Shape. On Windows, right-click the selected content and choose Mask with Shape. This will mask the image layer, revealing only the area within the square. To edit the masked content, double-click the masked layer.

Method 2: Creating a New Square Shape Mask

This method is ideal if you need to create a square mask from scratch.

1. Create a square: Use the Rectangle Tool (U) to draw a square on a new layer. Ensure this layer is above the layer you wish to mask.
2. Select your layer: Choose the layer you want to mask.
3. Create a mask: Hold down Ctrl (Cmd on Mac) and click the square layer's thumbnail. This selects the square shape. Then, click the Add layer mask button at the bottom of the Layers panel. This creates a mask using the selected square shape. Anything outside the square will be hidden.

Method 3: Using Quick Mask Mode (For Precise Masking)

For more complex or precise square masking, use Quick Mask Mode.

1. Activate Quick Mask Mode: Press Q to activate Quick Mask Mode.
2. Select a square brush: Choose a square-shaped brush from the brush tool options.
3. Paint the mask: Paint within the area you want to keep visible. The masked area will appear in a translucent overlay (usually red).
4. Exit Quick Mask Mode: Press Q again to exit Quick Mask Mode. This will convert your painted area into a selection, then to a mask.

Important Considerations:

• Layer Order: Ensure the layer you're masking is below the layer containing the shape used for masking (if creating a new shape).
• Mask Editing: Masks are not destructive. You can always adjust or remove a mask without losing the original image data.

This information is based on the provided references which detail using shapes as masks in Photoshop. The process is relatively simple and offers various techniques depending on your needs and the existing content in your project.