Dance In The Rain

My first attempt at wood burning. I just picked up a piece of untreated, pine, i think, at the local art supplies store. I don't know what the best kinds of woods to use for this though. The package my wood burning tool came in said to use soft woods. I did have some trouble with the grain of the wood. Some areas were so super soft, the tool sunk right in, sometimes too fast, I was probably pressing to hard, but I wanted it as dark as i could get it. And then sometimes it wouldn't burn, like over the darker grain areas. Does this make sense?

Any suggestions on best types of wood and maybe techniques?

I did stain it afterwards and applied a clear gloss to give it a nice finish.