Opacity and Fill are both used to control the transparency of a layer in Photoshop, but they affect the layer's contents and effects differently. Here's a breakdown of their key differences:
Opacity:
- Affects everything on the layer: This includes the layer's content (pixels, text, shapes) as well as any layer styles (drop shadows, strokes, bevels, etc.) applied to the layer.
- Reduces the transparency of the entire layer: When you lower the opacity, everything on that layer becomes more transparent.
Fill:
- Affects only the layer's content: This means it controls the transparency of the pixels, text, or shapes on the layer, but it does not affect any layer styles.
- Reduces the transparency of the content only: When you lower the fill, only the layer's content becomes more transparent, while any layer styles remain at their original opacity.
Think of it this way:
- Opacity: Like a dimmer switch for the entire layer, including any lights (layer styles) attached to it.
- Fill: Like a dimmer switch for the bulb (layer content) only, leaving the lights (layer styles) unaffected.
Why is this useful?
This difference allows for some interesting effects:
- Creating watermarks: You can add a bevel and emboss effect to your text watermark, then reduce the fill to 0% to make the text itself completely transparent, leaving only the stylish outline. This is a common technique for creating subtle watermarks.
- Controlling layer effects: You can use fill to adjust the visibility of a layer's content without affecting the appearance of its layer styles. This can be useful for various design techniques.
- Working with blend modes: Fill can be helpful when using blend modes, as it allows you to control the transparency of the layer's content without affecting how the blend mode interacts with the layers below.
