From: Sandy King (sanking@clemson.edu)
Date: 10/27/01-05:53:42 PM Z
Judy Seigel wrote:
>
>Anyway, Sandy, I, too, tested the BLB against the BL, and found the BLB 20
>to 25 % slower... in cyanotype. My neighbor began with the BLB and
>complained that they were slow. I brought him over my BLs for comparison.
>He thereupon switched to BL. Then I brought his BLBs over here and tested
>them again (also in cyano), and found similar results -- 20 to 25% fewer
>steps in a given exposure time.
>
>The tests were made with Stouffer 21-step & I have them on file.
>
>Here are my speculations about your unexpected findings ... First of all,
>you're using bulbs by two different manufacturers... that to me is more
>suggestive than anything about temperature or humidity -- which I find not
>particularly important within normal room conditions assuming exposure and
>development are PROMPT). The thickne & composition of the glass and source
>of the phosphors are almost certainly NOT the same.
Of course it is important that bulbs of different manufacturers are
being compared. I provided the information knowing that it was
important, aware that few if any have provided such details in the
past when talking about the speed of BL and BLB bulbs, as you did not
even now in describing your tests above.
>
>I don't know how many peppers (are they all fat or are some thin?) your
>program will afford the following, but IMO this project is NOT as simple
>as it might seem. There are hidden variables and booby traps (we now see)
>at every turn. If my results and your results are so different.... how can
>either of us speak for someone, for instance, in Brazil who may be
>usaing oddball old lamps, or getting them from some oddball gray market,
>or using a bellows & diesel engine for power, or maybe a cover glass which
>screens rays differently, or.... about a dozen other variables I'll think
>of one of these days...
I think the variables are not nearly as complicated as you suggest.
In fact, what I am reporting has been very consistent across a wide
number of processes, and repeated several times. The important point
is that all of the processes I have so far tested responded in a very
consistent way to the four different lights. The key is precision in
specificity as to the make and type of the comparing bulbs, which
information I have provided, and age is clearly a factor. It may be,
as you have stated in a previous message, that the devil is in the
details. The genius may be in being able to see and understand the
forest and not trip over the bushes.
Sandy King
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