How do I apply an image effect to just one object?

..without affecting the rest of the screen. For example I want some text to glow but not the other objects. I have tried using multiple cameras with different layers but but cameras still seem to be affected by the effect. Anyone know?

There are many threads in the forums about "Selective Glow", and a few questions already here in Answers. Here is one I submitted an answer for.

Basically the way the Glow Post-Image-Process effect works is in the alpha channel of the final render, where objects that are more opaque(white) will have more glow applied.

The trick is getting only the objects you want to glow to render with an opaque alpha channel.

Every material which has a _Color property has RGBA value, if you don't want it to glow set it's A value to 0, otherwise anywhere above 0 up to 1 depending on the amount of glow you want applied.

Don't worry, as long as the shader you are using isn't already using the alpha channel to render the object transparent or translucent it won't make your materials see-through. If you are, you are going to have to use an additional material (and render pass) to override the alpha of the object after-the-fact to make it work. This can be tricky but I explained it and provided the shader code in my link above.

Hope that helps.