Is the light intensity from inverter type welders different from transformer type welders?
I've seen this myself and agree, yes, there is a difference in the light outputs between inverter and transformer type welders (even at the same amperage setting). I also have seen a difference between different models of inverter MIG welders.  I don't precisely know what makes the difference, but I am guessing it has to do with differences in the switching characteristics. Also, different types of welders have different output... e.g. a stick welder, IMHO, seems to have much more UV output (at least the ones I've used).  I can get a bit of a "sunburn" from only a couple of sticks if I don't make sure to cover up.  I've never had that happen for an equivalent amount of welding on a MIG.

But we need not rely on anecdotal evidence...  The link below is to a paper published by the German equivalent of OSHA, where they actually measure the light output from various welders at 180 Amps. 

http://bit.ly/1zKakL1