Re: update: screw-in BLB light-box

From: Richard Knoppow ^lt;>
Date: 08/01/05-03:19:08 PM Z
Message-id: <003601c596de$aa5c29c0$2d695142@VALUED20606295>

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Sent: Monday, August 01, 2005 7:33 AM
Subject: update: screw-in BLB light-box

> Hello Sandy King (who first posted a query about the
> screw-in BLBs as a possible source of UV for alt
> processes) and anyone else interested in knowing how they
> worked.....
> This past weekend, during an excellent workshop on PT/PD
> printing taught by Kerik Kouklis at the Cascades Academy
> of Photography, which is located in lovely "old town"
> Issaquah, Washington, I was able to compare printing times
> in my lightbox (6 screw-in 13 watt BLBs with the print
> frame 4" from Light source) with one of Edwards
> Engineering fluorescent tube boxes. Needless to say, the
> times were longer - a tad more than 10x - but the results
> were the same.
> Stated specifically: A digineg created with Keith
> Schreiber's method (looks orange on screen but prints
> yellow-green) and printed on Pictorico OHP using an Epson
> 1280 (dye inks) with 100% PD soln. on Cranes "Platinotype"
> (B&S name for this paper) required 1 min 50 sec in the EE
> box, where as the same required 20 min in my box. All
> other factors were more-or-less (read "unscientifically
> determined to be" ) equal.
> For the time being, as I perfect coating techniques, etc.,
> I am not bothered by the excessive time - gives me an
> opportunity to make notes which I tend to forget to do
> when I am working at a faster pace - but will most likely
> give the 20 watt bulbs a try before building a larger tube
> box.
> Anyone know right off the top of their head if I might
> expect exposure vs wattage to be linear in this situation
> (i.e., will the increase from 13 watts to 20 watts cut my
> time by about one-third)? If not, I will go back to some
> of the published data / manufacturer's data to search out
> the answer to this question. If it is less than linear, I
> probably wont bother with the more expensive screw-in
> bulbs, but just go right to a tube box sometime in the
> future.
> Thanks!
> Judy
> --
> Judy Rowe Taylor
> Mukilteo, WA
   Judy, does your light box have any sort of reflector in
it? It seems to me that without a reflector most of the
light output of the compact flourscent lamps is wasted. My
first thought is to use small reflectors around each lamp,
something along the lines of the small utility reflectors
hardware stores sell. One would have to make sure they were
reasonably efficient for near UV. Aluminum is good, not sure
about other materials. There certainly must be other and
better ideas about how to do this.

Richard Knoppow
Los Angeles, CA, USA 
Received on Fri Aug 5 12:09:48 2005

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