We’ve long had ways to build layer masks in Photoshop Elements, but they’ve always been workarounds, whether via adjustment layers or add-ons like Grant’s Tools. In Elements 9, Adobe finally added true layer masks, which you can add instantly via the Layers panel.
In a nutshell, when you want to work on a mask, click on the layer mask in the layer you want to work on and select your Brush tool.
When working with masks, “White reveals, black conceals.” Anywhere you paint black with the mask selected in the Layers palette, you will conceal the changes you’ve made, allowing the original layer’s pixels to come through. Anywhere that you paint white reveals the changes that you’ve made. So, to work on your image, just set your Foreground and Background colors to black and white (press the D key if they aren’t, and press X to swap the foreground/background colors). Then you can start painting on your image and the effects will be applied to the layer mask.
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