Those look quite well actually, but I see a lot of areas that are pixelated and could have been blurred, like in the first one, where the outlining of the head meets the body, and on the second one where the edges look red. When using a render always try to feather the edges and blur as much as possible to make it look natural. Also on the first one, there is green in the background, but you could've overlayed part of the background over the, uhh.. (Person?), the render, so that it doesn't look so out of place due to the back that it's colors are light, while the background is darker. The font is good, but unless the two signatures are together in a set of some sort, try to steer away from using the same font, and some fonts look better on different signatures than others. Sorry if my criticism is confusing, I'm not exactly familiar with all the terms

. But overall I'd give the first one a 6/10 and the second an 8/10. Keep it up