RE: good source for UV tubes?

From: Sandy King ^lt;[email protected]>
Date: 01/14/04-11:27:55 AM Z
Message-id: <a06020405bc2b211e3142@[]>


> -- or conclusivized me.
>However, I gather now that you're saying the BLB was (however much)
>slower, but did ultimately come to same or nearly same scale. Friend was
>doing editions... growing old while waiting for the BLB to print. I
>myself wasn't interested in what I could get after 45 minutes... which if
>I read you correctly is what you're saying here?

Yes, there is no doubt but that the BLB tubes print slightly slower,
about 10% or so, than the BLs. But if anyone claims there is a big
difference, say of 25-35%, then I think (no, I know) their tests were
somehow flawed. I have no doubt but that you observed what you say
you observed but bear in mind that normal fluctuations in voltage in
some homes can account for up to 15-20% difference in output. I have
eliminated that important variable in my own testing by correlating
exposure time in seconds with light integrator values in units. Plus,
I have made the tests many, many times.

Also,if you look at a Spectral Powder Distribution chart of these
tubes you will see that they are virtually identical in the
production of UV radiation below 420nm. The BLB tubes filter out all
radiation above about 420 and this accounts for the slight loss in
printing speed. And the amount of the loss could be predicted merely
by examining the intensity and location of the peaks in radiation.

> But, I'm wondering if you found gum also the same with both
>bulbs. I've seen a difference in color intensity AND scale with gum by
>different lights, as have others, about which more in future. Meanwhile,
>am I correct that you DO agree the exposure time is quite different?

I have not observed any difference in color intensity between BL and
BLB tubes with any of the processes tested. As for contrast, BL tubes
may give just a tad more contrast, but this is a characteristic, not
a good thing or bad thing, since the small differnce can easily be
adjusted in printing.

Received on Wed Jan 14 11:31:49 2004

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