Transparency & Opacity

[davidtayhs]

Appreciate help understanding if these two parameters are dealing with the same feature.

When starting a new picture, I can click on the Colour window and alter the transparency setting for the Primary or Secondary Colours. This affects the tool that I'm using e.g. Text tool.

When I go to the Layers-->Layer Properties window, I can adjust the opacity setting. This affects everything on the layer.

When using the Drop Shadow effects, I read that you need a transparent background. Tried doing this on the original layer without any shadow appearing. Lowered the opacity setting for the layer and found the photo fading but no shadow appeared.

But when a new layer is created without changing any property setting, the Drop Shadow effect works beautifully.

Don't understand the difference in results! Is it caused by some opacity or transparency differences between the original and the new layer?

Appreciate info.

[Rick Brewster]

The opacity of a layer affects how it contributes to the image composition, but does not affect the actual pixel contents (the pixel values). The tools in Paint.NET are "blind" to a layer's opacity setting, and work with the actual pixel values. This is especially pertinent when working with different layer blending modes. You may use the "Difference" blend mode, and the color you see on screen could be black, but the actual pixel value of the layer at that position may be something like white or red or whatever.