So... as promised, a quick step-by-step of the volcano:
Each of these images represents a different layer/step in the process. Generally, I copied a layer to make the changes necessary for the next step. The green part is just a layer in the background... I don't do anything with it, and most everything else is on a transparent layer over that (it's there in the image for contrast).
So, started with a blob of 50% gray where I'm putting my volcano:
I use the Alpha select on the layer to get the whole blob, then I perform an angular gradient fill with black and white.
I make a copy of this, and redo the angular gradient with two mountain colors (I'm mostly using colors from the city-map-palette available for DL in RobA's regional map GIMP tutorial). I keep both layers, but leave the B&W layer invisible.
Then, using a copy of the B&W layer (which, to work on, now has to be visible, but it will be invisible in the final image), I use Joe's method of using the smudge tool to smudge up and down along the outside of the mountain cone. This will make those ridge ripples on the cone later. Then I use the dodge/burn tool, set to burn, and burn a small, darkened spot at the tip in the midst of the white. The burn is subtle, but I think you want it subtle, because too much will appear too deep on the bumpmap. I also went back around the edge of what will be our crater with the dodge tool (set to dodge) to lighten it up a teensy bit. I also did some Noise>Spreads and Gaussian Blurs at some point around here. You just kind of get used to doing those two, in that order, after going through RobA's tutorial.
Then, I made a copy of the original gray blob (I kept a copy of it hidden in the background), and applied a bump-map filter using the previous layer.
Set this layer to overlay, and hide all the other layers except this, the mountain color, and the green background. However, I didn't totally like the results of this (I think this is partially the source of the "floating mountain" phenomenon), so I went back to the B&W gradient. I'll show what I did next in the next post.
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