Final answer:
To mask out a portion of an image on a layer without permanently removing the pixels and to have soft edges for a smooth transition with other layers, you should create a layer mask.
Step-by-step explanation:
To mask out a portion of an image on a layer without permanently removing the pixels and to have soft edges for a smooth transition with other layers, you should create a layer mask.
A layer mask allows you to hide or reveal parts of a layer by painting or editing the mask itself. It works based on grayscale values, where white reveals the layer and black hides it. Shades of gray create a soft transition between the hidden and revealed areas.
To create a layer mask, select the layer you want to mask and click on the 'Layer Mask' button at the bottom of the Layers panel. Then, use the Brush tool to paint with black or white on the layer mask to hide or reveal specific areas of the image.