I remember learning to make drop shadows with Photoshop, v1.5 or 2 before layers (v3?) — I can't remember. My tutor was Luanne Seymor Cohen at Adobe. You had to make your selection (manually), create two channels, offset and blur one channel, subtract one channel from the other, load the channel as a selection, fill the selection, and adjust the opacity of the fill. Deselect — something like that and you were a King if you had the know-how. Tech has passed me by — glad I'm a year to retirement.