RE: Light source for big prints

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From: John Campbell (tojohn@texas.net)
Date: 03/19/02-12:53:12 PM Z


Keith-
That's what I thought you meant. I don't think you'll have a gap at all,
given a 4" clearance and end gap of 2". It would be similar to having your
tubes on 2" centers, which causes a one-inch center of diffusion, which is
of no consequence at all given how all those happy little photons are
crisscrossing each other. AND, there are fixtures available that would
allow you to butt them right up against each other with less than a one-inch
end gap.

Failing all else, I've heard that the Sun is a reliable source for prints of
large dimension.

Some time back we had a lively exchange going here re the question of
clearance distances from tube light sources. I bet a million monopoly
dollars that clearance was not an issue up to fractions of an inch from the
tubes. The proceeds should allow me to retire early to Park Place.

Go easy,
--John

http://www.photogecko.com/
Home of The Gecko UV Light Box
"Get The Gecko!"

-----Original Message-----
From: Keith Gerling [mailto:keithgerling@att.net]
Sent: Tuesday, March 19, 2002 2:34 PM
To: alt-photo-process-l@skyway.usask.ca
Subject: RE: Light source for big prints

John,

My intent was to minimize (hide!) the appearance of a line going down the
middle of the print. The fixtures would be butted together, but that would
still leave a 2 inch gap of no light emission - the bulb holder, and the
ends of the bulbs temselves (bulb is 22" - fixture is 24")

I wasn't aware of the 48" fixtures. Thanks. I'll look into that.

Keith

-----Original Message-----
From: John Campbell [mailto:tojohn@texas.net]
Sent: Tuesday, March 19, 2002 9:40 AM
To: alt-photo-process-l@sask.usask.ca
Subject: RE: Light source for big prints

Keith,

If you are building a new array from scratch, why not use 48" fixtures and
40-watt tubes? I recommend Phillips product number 046677-30108-5, which is
a super actinic radiation source available in 48-inch lengths. I don't
think you'll have any problem with lengthy exposure times!

FWIW, I don't really see a problem with your staggered graphic-but I wonder
why you would need 2 1/2 inches between the fixture ends. Maybe I'm not
getting your intent.

Good luck,
-John

http://www.photogecko.com/
Home of The Gecko UV Light Box
"Get The Gecko!"

-----Original Message-----
From: Keith Gerling [mailto:keithgerling@att.net]
Sent: Tuesday, March 19, 2002 12:08 PM
To: alt-photo-process-l@skyway.usask.ca
Subject: Light source for big prints

Currently, I use a bank of Sylvania 20w Black light bulbs, which
provide coverage for 22x30 in prints. As I now have a need to print 30x40,
I am considering alternatives. One option would be to go to another light
source (yard lights, etc.) but I am concerned about lengthy exposure times.
As I am comfortable with using the flourescent source, I am wondering if
there might be a way to build a larger light bank using 22 inch bulbs. My
question: if I were to line up two banks side-by-side, and stagger them by 4
inches like this:

                   ============ ============
                 ============ ============
                   ============ ============
                 ============ ============

                                       etc,

what are the chances that the gap between banks (approx 2 1/2 inches) would
be "filled in" and not effect the print. Currently, the print is about 4
inches from the light source.

I'd appreciate any other ideas.

Keith


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