Hi!
I used to believe that kelvin ratings were somewhat accurate, but the past two years or so has shown that this is just and only just a marketing scheme, at least for some of the new bulbs.
The Aqualine bulbs are supposedly a tinge bluer than the Ushio/Hamilton 10K. I suppose Aqualine *things* or *guesses* that this is 13K. I doubt that it's as blue as the 12K.
Champion Lighting did all of us a disservice by labeling their bulb as "10+K". This bulb is more like 12.5K since it's a tad bluer than the 12K but almost EXACTLY the same colour.
I don't think the Aqualine ""13K"" bulb is as blue as the Blueline 10+K or the ALS SunBurst 12K. I could be wrong about this though, but I don't think so.
My favourite is the "True German" 10K Ushio. A perfect colour in my opinion. The Iwasaki (the new DL version) is not too bad, but it really truely is a little greenish and not as "white" as the Ushio, but it's not as bad as I thought it would be. Either of these would work out just fine, but the Iwasaki really does need *some* sort of supplementation to look appealing.
-Nathan