Ok, so... looking at the three, I noticed something in hindsight which hadn't been immediately apparent to me at the time. When rendering each f these, i was trying to get a similar look from each one. In so doing, all of them seem to require a 'value' of 8 for the glowing object - whether it be from the ambient calue, the probelight's exposure, or a multiple of the two combined. This would account for the closeness in appearance betwen the renders. That said, there are small differences between the ambient only one and the two using the problight. In some areas, such as the inner ring of the 'o' (I'm looking on the wall here), the ambient only render loses definiton slightly, resulting in a less distinct 'hole' in the middle. Although it's very close indeed (probably as a result of me mucking about with the 'brightness' settings), for my money, I think the alt diffuse one looks the best by a tiny margin. jonthecelt