Stage 3 – Texture and trim to size
Go back to the Land layer – one of the darker sets of clouds, whichever one you picked. We're not starting with the ocean because it operates differently.
Duplicate it TWICE, so you have a total of three identical layers.
In the layers window, hide (uncheck) everything except these three.
Leave the bottom one alone for now. We'll be using it for color later.
On the second one, run Effects > Stylize > Engrave/Emboss.
I generally prefer to emboss at 5 pixels width, but that's a matter of taste – also, a fun area for a Tweak Alert. Five pixels gives you nice height distinctions, but maybe you want to make your lowlands more smooth, say with a 2 or 3 pixel Emboss, then emphasize your higher elevations with the 5-pixel. Up to you.On the third layer:
Rename this layer to Land Texture.
Run Effects > Color > Threshold, with the default settings.Move one of the mask layers down so that it is between the clouds (land) and the embossed layer (land texture). From top to bottom, you should have Land Mask, Land Texture, Land Mask, and Land.
Run Effects > Alpha Mask
Rename to Land Mask.
Select the top Land Mask, and Merge Down onto the land texture.
Select the other Land Mask, and Merge Down onto the land. You should now have two layers, one called Land Texture, and the other one called Land.
Our masks work by giving you a transparent area and an opaque white area. Once our layers are merged, we don't need the white anymore, and we really don't want it to keep our other layers from showing through, so let's fix that.
From the tools window, change to Magic Wand, and set the tolerance to 0.For another Tweak Alert, and this can be fun, you can leave a few of these white areas, especially the ones inside landmasses, to serve as plains later on. Trust me.
Select anywhere in the white part of the image; if there are multiple areas, you can hold down the CTRL key to get them all. Alternately, you can set the mode to "Global" and get everything with one click.
Hit "Delete".Repeat on your other merged layer.
Behold, grayscale embossed landmasses – nifty!
Hide these layers.
Go to the next cloud layer and repeat the above steps:
Make it visible.
Duplicate twice for a set of three
Emboss the middle one, and label it Texture
Threshold, then Alpha Mask on the top one, and label it Mask
Duplicate the mask and move one of them down
Merge the masks down, one onto the texture and one onto the clouds
Magic Wand, select and remove the white areas
Hide these layers and move on to the next.