Re: update: screw-in BLB light-box

Hi Judy,

Thanks for the update. Were the screw-in tubes your unit placed as
close together as possible? This be taken into consideration in
weighing the pros and cons of the screw-in versus regular tubes.

The use of 20 watt screw-in tubes in place of 13 watt ones should
reduce your exposure by about 1/2, but if your tubes are already
placed together as closely as possible that still would not reduce
your exposure times to what you observed with the Edwards unit.

Sandy

>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
Received on Fri Aug 5 12:10:04 2005