Text Not Blending Properly

You didn’t really mention how you’re rasterizing and blending your text onto the framebuffer. But I suspect pre-multiplied alpha blending and/or an sRGB framebuffer will resolve your issue. Read this post for more details (including screenshots and tutorial links):

Note: the last few posts in this thread discuss sRGB framebuffers, why, and what you get if you don’t use one.