Aye, I'm having a difficult time with this one, I'm curious if anyone know how to produce transparency with an image map? Like, when blending wireframe shots with rendered shots? I know I've seen it posted before, or maybe i saw a tutorial on the subject, but how do I tell Photoshop to drive the transparency with an alpha channelor image map? You know, so that the grey level corresponds with the transparency level? Does this make any sense?

load the channel as a selection and then hit the delete key on the layer which needs the transparency. remember to keep a copy of the layer though. just in case you don't like the result. drag the channel onto the load as selection button at the bottom of the channel pallette to load it as a selection.

You might as well load the channel as a selection and hit the mask button in the layers tab. This gives you a mask. Without the need to store a copy of the layer. Masks are great for that. Copy and past works also. As long as you alt-click (or something similar, I am on Mac) on an empty mask to 'jump in', that is. Otherwise the alpha channel will be pasted in a new layer.

Attached Link: http://www.moonshinetraveller.ch

another way : duplicate your working layer / change to quick mask mode" / apply whatever you need as gradient / change back to nomal mode = you get a fading selection - delete as much as you need...