Mapping in Paint.NET - a basic tutorial

[PeaceHeather]

With each successive set of layers, running Threshold will produce smaller and smaller black areas. You will reach a point where, when you run Threshold, you only get a blank white layer. That's okay, it just means that you've hit the upper limit of your usable layers, and since we're really only going to want four layers anyway (at least, for this tutorial), that's not a problem. Just delete any layer that gives you a totally white threshold, and get ready for the next stage. In fact, if you want to, you can start with your brightest layers, run Threshold, and delete them if they come up white. As soon as you get a usable layer, Undo Threshold, and then go back to the steps as I've described them.

[TWEAK ALERT: Try adjusting the threshold settings to be more forgiving, allowing larger black areas, and using those settings to create more than four layers. In theory this should give you more detail and subtlety between the different elevations.]