What is the effect of adjusting fill opacity on a layer?

Adjusting the fill opacity on a layer directly influences the visibility of the layer’s contents while leaving any layer styles or effects applied to that layer unaffected. When you modify the fill opacity, you are essentially controlling how transparent the actual pixels in that layer are, rather than the effects or styles that have been added. For example, if you have a layer with a solid fill color and a drop shadow effect, reducing the fill opacity will make the color of the layer more transparent but will maintain the visibility of the drop shadow, allowing it to remain opaque. This distinct behavior is key for achieving certain visual effects, enabling artists to create complex compositions without losing effects applied to layers.

The options regarding layer styles and effects, the removal of styles, or adjustments to color balance reflect a misunderstanding of how fill opacity and layer effects interact within Photoshop.