Layer is semi-transparent, but the opacity is at 100%

[DigitalChickster]

This is driving me crazy! Take a look at the attached screenshot. The light blue block of color is obviously somewhat transparent. But if you look at the layers palette to the right, the opacity is at 100%. The blending mode is "normal." What else could be causing it to be transparent? Thanks! 

[Semaphoric]

Every pixel in the layer has the three color channels, and also a transparency channel. This is separate form the overall opacity of the layer.

You could do this with a selection on an empty layer, and use Edit > Fill with an opacity setting less than 100%.

[Trevor.Dennis]

John, when would this approach be useful over using layer opacity of a layer mask?  I remember a while back when we had a long thread about Displacement Maps, and you spoke about using colours as oposed to grey scale maps.  So is this an area you are interested in?

Here you go.  I found it.

[Semaphoric]

It seems to be an old-school way of doing a layout. I can't think of a reason to use this over a Solid Color fill layer with a mask.