Texture baking - losing image quality

I have a problem so the final bake product is a texture that lacks some details of original textures. Now, I’ve assigned lot of materials onto an object, about 50, maybe that’s the problem?
Anyway, these are the steps how I baked textures.

First I’ve assigned each of materials and mapped each texture, and I was almost ready to bake

Next thing I needed was a new uv map where I selected the whole object and “smart uv projected”. After that I’ve chosen the image onto I wanted to bake and clicked the Bake button. And here is what I got…

So the numbers have disappeared! I’ve tried to create an empty image for baking and set it’s size to 4096x4096 but the same happened.

Does anyone know what could be the solution?

Without seeing your file - i doubt. Unwrap in the first image looks confusing to say at least.
Why do you have 50 materials? What was the reason for such a variety?
Meanwhile there’s one based on your design, hope helps a bit. http://www.pasteall.org/blend/36501