It's also good to note, with luminous surfaces, you may need to have a duplicate object set to invisible, and use it as your emission, by that, I mean your actual light level above Lum=1. So your visible object will have luminosity at 1, or whatever level, masked by whatever, and then your hidden object will have luminosity at say 1000 to create a very strong glow, while your render shows and normal glowing object. Anything above 1 in lum tends to just be a solid, un-detailed thing.