How to make a transparent alpha channel

JuliaS2000  wrote I have a logo with a transparent background. I adjusted the fill opacity to 50% and then made an alpha channel from it.  My alpha channel appears in my Channel tab as 100% opaque, no transparency.  How do I create an alpha channel with a certain level of transparency in it?

What are you trying to do? What will your Alpha channel be used for. Why do you need an Alpha channel for a logo? Alpha channels are Grayscale maps,  Black Completely empty nothing, White 100% Opaque no Transparency. Shade of gray map  transparency levels. Alpha channels are saved selection..  You can Ctrl+Click on your LOGO layer content  in the layers palette to load the layers transparency as a selection and save that selection as your logo Transparency Alpha channel.

An Alpha Channel are a grayscale raster image like layer mask they are a like a section.  White Fully Selected, Black not selected, Gray partly selected.  You can actually save a selection as an Alpha channel and you can load an Alpha channel as a selection.

If you want a 50% opacity Alpha channel, then fill a layer at the top of the stack with 50% grey, and drag any channel to the new channel icon.  Then delete the 50% grey layer.