After creating the mask and applying adjustment, you can also adjust and change layer mask using selection tools or, the most common way, using brush tools. To have a more accurate preview of what are you doing, Alt + click on the layer mask thumbnail to show the mask in the image area. At this point, you will have a layer mask on your screen in large view, so it is easy to fine tune it, but you wont see how that affects your image. To seean instant preview how changes on layer mask affects the adjustments, use New Window for (name of your image) from Window > Arrange. Here is a more detailed tutorial on the topic: New Window for.. Command in Adobe Photoshop.
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