Layer Masks are a powerful tool that give a lot control with our adjustment tools and composite images. A layer mask can be used to hide or reveal the affects of an adjustment tool. When we stack images in the layers pallet, a layer mask is one of the tools we can use for how images interact with images below.
When you open an image in PS it appears in the layer pallet as a single layer titled Background. You will see a small thumbnail of your image.
Layer mask can be created for any layer in an image opened Photoshop. To create a layer mask click on the icon on the bottom of your layers pallet that has a circle inside a rectangle, it looks like a Japanese flag. You will see a white box appear the left of your thumbnail, this is your layer mask. Layer Masks are a tool found only in PS and are not available in Lightroom.
Simply put, when you paint on your image with black, you will see what is in the layer below. A Layer Mask allows you to target witch part of a layer will influence the layer/layers below and to what degree.
When using a Layer Mask you’ll need to know a few things about the Foreground/Background color picker boxes, as well as the brush tool.
The color picker boxes (my term) are found in the bottom of the tool bar.
The color on top is the color the Brush Tool will paint with, in this case red.
To switch the Foreground and Background Colors, click on the double arrow key that’s above and to the right of the boxes. (The shortcut is ‘X’)
The default Foreground And Background Colors are black on top and white behind.
Click on this icon that’s above and to the left of the Foreground/Background Boxes:
When painting with a Layer Mask you’ll need to have the color black on top.
Once you have black on top, hit the B key to select the Brush Tool in your tool bar, or click on the icon of the brush.
Each tool has it’s own menu bar for that tool. The tool menu bar is just below the application menu bar at the top of your screen. In this example the opacity slider is se to 10%.
When you paint with black and you have your opacity slider for the brush tool set to 100%, your brush stroke will 100% reveal what’s below. Painting with black at 100% opacity is like cutting a hole in your layer to show what’s underneath. If you paint with your opacity slider at 0%, nothing will happen, you’ll get zero effect. If you paint at 50%, you’ll get a partial transparency, seeing some of each layer.
Here I have added a layer beneath the image that is a solid blue color. In this image I have the Brush Tool selected, the opacity slider for the tool is set to 100%, the Foreground Color is black.
Notice that the layer for the color blue is selected and the thumbnail of the blue color is selected.
To paint on the layer mask, I need to first select the layer and click on the layer mask to the right of the thumbnail of the image. I am now ready to paint over my image with the paint brush. If I click on the thumbnail and paint, I will be painting on the image, not the layer mask.
The saying is ‘black reveals and white hides’. When you first create your layer mask it’s totally white, the layer below is completely hidden.
Painting with black and having your brush opacity set to 100% will reveal 100% of the area below the area you have painted on. Painting with gray or with the opacity slider between 0 and 100%, you will partially reveal the layer below.
Painting with black and the tool’s opacity slider set to 50%, makes the a transparency the sees only partially the layer below.
One last thing I want to point out is the Brush Tool’s hard and soft edge options. In the tools menu bar you will first see the icon of the tool you have selected in the in the tool bar. Here we see a picture of a brush on the far left.
Clicking on the box to it’s right will give you a drop down menu with 2 sliders for brush size and softness. The number in the box, this case 45, shows you the brush size you have set. The Hardness slider when to the far left will give you the softest edged brush, and to the right the hardest. Notice the white circle over the brush size number will change accordingly to show how hard or soft the brush is.
Learning how to use a layer mask will give you a powerful tool to use when working with layers in Photoshop.