Alpha Map/Node Editor help

[squeegie]

Im havng some trouble with Node Editor and Alpha Maps.
Hope some of you node gurus can steer me in the right direction on a few things.

1) Alpha Maps/ PSD files:

If I have a layered PSD file with an imbedded Alpha Map, is that map represented by the "Alpha" connector in the "Image Map" node?

2) Using Grayscale images as Alpha Maps:

once again, do I just attach the "alpha" connector to the node that I want to what I want to clip out?

[Danner]

Think of alphas as a separate grayscale image that comes with your image that determines it's transparency, also used to define a photoshop type selection.

In lightwave it is used to mask out a surface to let another surface through usually, and it affects the Alpha output on nodes.

You can use non 32bit grayscale images to do the work of alpha enabled images, there is no alpha in them so no information will be coming out of the alpha output on their node, so you need to use the color output from them.

As far as using PSD.. I usually use PNGs wich have a simple to use alpha channel, and have lossless compresion to boot.