Ok I tried blurring the background and bluring parts of the body so that the render fits in with the background. Then I sharpened a part of the render so that it looks like he is popping out. Which one is better, with or without border
I like the one without the border better. The background looks out of place with Aang though. The colors on Aang are really vibrant and the BG is B&W. You did a good job blurring the render to fit in with the BG but the render and BG don't seem to fit in to start with. And you like that render... don't you? I really like the sig though. Just a better BG.
If the background was colored it would be better. I like it without the border becuz it looks a lot better
All of the render is in the same place depth-wise, so the blur like that wasn't necessary. Take reaper of bunny's sig for example, as the render goes farther back, it's more blurred.
Don't blur and then sharpen what you blurred. That lowers the quality. Instead, copy the signature, make a new layer, and paste it. Then blur the new layer, and ERASE the parts that you want to be sharp.