From: Richard Sullivan FRPS (richsul@earthlink.net)
Date: 09/29/01-12:54:30 PM Z
Steve,
This is a repeat of the message that I sent to the carbon list a while back:
Note that this a basically a one hammer project and I am assuming that if
you've gotten this far with carbon printing then you can work out the
"engineering" details.
Any electrical wholesale house carries the units but Grainger is a good
source and they have warehouses in most big cities. I think you can still
order at the counter without an account.
You will use a standard 1000 watt Luminaire. These are not your everyday
garage security lights. If you have ever been in a Home Depot, look up,
there is about 100 of them up there, they are the standard metal halide
lights used in supermarkets etc. (Just think of the power used, 100 1000
watt units!)
Grainger No: 7v197 $197.00 page 901 in the 2002 cat
Grainger No: 2v754 $87.66 page 812
Essentially what you want is the cheapest standard light unit. The standard
ones are the least expensive. I think they also refer to them as "high-bay"
in the designation. "Low bays work but costs more.
Switch and wire plus some plywood at $25.00 brings the total to @ $310.00.
You may beat this price by finding one used at a wrecking yard or salvage
place or a new one for less locally at your wholesale house.
The number of the bulb recommended for the lamp on page 901 has apparently
been superceded by the one listed as they have not updated the reference on
pg 901.
The lamp is a multi tap. There will be wires coming out, one a green ground
wire and some others marked 110, 240, etc. Use the common, the ground and
the one for the voltage you are using. Wire it up with a plug and switch.
If you're getting lost here, get help, it's basic but don't attempt this if
you do not know basic wiring.
You will need to suspend the unit about 20 inches from the print surface.
The 20 inches is from the light pod in the bulb. You can hang it, build a
box to set it on or whatever, the engineering is up to you.
The light is bright but not dangerous. A pale skinned person could lay
under it all day and not get a suntan. You will want some sideways
shielding for the light as with any very bright light you do not want to
look directly at it.
When you screw in the bulb screw it in firmly. It's a scary looking thing
but it is not under pressure and does need to be in firmly as any arcing in
the socket can cause problems. It will take about 6 minutes to come to full
brightness. If shut down it will take that long to restart. It is best to
let it cool for a few minutes if shut down before restarting. If you turn
it back on nothing will jappen for a few minutes so don't panic, the light
is still good!
These units are only good for a "managed" printing situation. A timer goes
off and the print is manually removed and the light stays on. Most of us
print this way anyway. There is a lot of light coming out and the illusion
is that there is a lot of power being wasted. Yes, some is but those little
heaters we use in the office in the winter under our desks are 1500 watts
so these use less that most space heaters. art is what makes us human so
the energy is being put to a good use.
Ask more questions.
--Dick Sullivan
At 11:19 AM 9/29/2001 -0700, you wrote:
>When I go into the store to buy, what do I ask for in a metal halide light
>(bulb?) versus a mercury vapor light (bulb)?
>
>Metal halide? Does that describe what we refer to as 'halide' lights?
>Meaning: Do all halide lamps produce UV light capabile of resolving to
>expose Pt/Pd emulsions?
>
>
>Steve Shapiro, Carmel
>----- Original Message -----
>From: "Richard Sullivan FRPS" <richsul@earthlink.net>
>To: <alt-photo-process-l@skyway.usask.ca>
>Sent: Saturday, September 29, 2001 10:45 AM
>Subject: RE: UV light and Contact Frame
>
>
> > Packing UV tubes close together does increase the out some but not as much
> > as one would expect. A good trick is to make a double bank. You'll need to
> > use the ballasts and stand-offs for the bulbs but in effect what you do is
> > use both sides of the light bank. Build a holder for your print frame and
> > you can print on top of the bank as well as on the bottom. Of course
>unless
> > you do both prints the same exposure you will need to do what I called
> > managed printing. That is the light bank stays on and you remove the print
> > from the light when it is cooled.
> >
> > I had a bank like this in California that I bring with me to New Mexico.
>(I
> > took out the light unit and never rebuilt it.) It was a work bench with a
> > glass top and tubes ran underneath the top. There was also a shelf
> > underneath the tubes. I could print on top or on the shelf underneath. As
> > you can see, if the tubes are close together all the light coming from the
> > upper portion of the tubes is lost in a one sided system. Most people do
> > not concern themselves with printing on this scale but if you are printing
> > a portfolio for sale as I did in the late 70's (Harry Smith San Francisco
> > c. 1906) then you are looking for production capability. I was jumping
> > around like puppy dog in a room full of rubber balls - coating, printing,
> > washing and drying. You can for production make up for print speed by
> > having print space in some cases, specifically where you need to print
> > different negs but if you want to make 25 prints of the same neg then the
> > difference between a 1 hr exposure and a 10 minute exposure is
>significant.
> >
> > Some points:
> >
> > Flat bight clean white is more reflective than shiny aluminum or any other
> > metal including a mirror. Use a base white paint, the one they use to add
> > color to for room walls.
> >
> > A fl tube bank is only a point source when the bank is far enough away to
> > look like a point. In other words at close distances, say for a 2 ft x 4
>ft
> > bank, for anything less than 16 inches, the distance from the bulbs is
> > insignificant. At 10 inches or 6 inches or 2 inches doesn't matter much.
> >
> > With a good white reflector behind the tubes you can space them about 1
> > tube apart and get about a 30% loss of light.
> >
> > Semi collimated lights with a reflector give more "luminous" prints,
> > especially with thick emulsion processes like carbon and gum, or POP. This
> > is due to the image being projected from one direction of light rather
>than
> > scattered light.
> >
> > So if possible forget fluorescents. If you are serious and have the space
> > go with a industrial metal halide light like Sandy built, it's cheaper,
> > easier to build, faster in print speed and some would argue gives a better
> > print.
> >
> > --Dick Sullivan
> >
> >
> >
> >
> >
> > At 08:26 AM 9/29/2001 -0500, you wrote:
> > >Not at all. At least none that I can perceive. I'm using a fluorescent
> > >tube bank, four inches from the glass, so light is flooding into the
>glass
> > >from all directions. Any minute distortions would be averaged out, I
>would
> > >think.
> > >
> > >A while back, when I was having problems with the lights "coming on",
> > >someone suggested aluminum foil be placed under the light fixtures, to
>which
> > >someone else warned about the problem of errant reflections and hot
>spots.
> > >As a crude test, I developed a sheet of paper that I had evenly coated
>with
> > >kallitype sensitizer, and used the heavy glass. Exposed for a middle
>gray,
> > >I saw no problems with evenness of lighting. I did catch some problems
>in
> > >my coating procedure, though...
> > >
> > >-----Original Message-----
> > >From: Judy Seigel [mailto:jseigel@panix.com]
> > >Sent: Saturday, September 29, 2001 2:13 AM
> > >To: alt-photo-process-l@sask.usask.ca
> > >Subject: RE: UV light and Contact Frame
> > >
> > >
> > >
> > >
> > >On Fri, 28 Sep 2001, Keith Gerling wrote:
> > >
> > > > All of my printing of late has been on 22x30 inch paper. I use a
>28x28
> > >inch
> > > > piece of "coffee table" glass that is almost a half inch thick, and
> > >beveled
> > > > on the edges. Incredibly heavy and awkward, it takes a bit of
>practiced
> > > > coordination to move it around, but it seems to do a good job of
>holding
> > >the
> > > > negative flat. I use a piece of carpeting underneath the print. One
> > >thing
> > > > is for sure: you won't need to worry about weights or rubber bands. I
> > > > bought this glass at a place called "Hobby Lobby" that specializes in
>silk
> > > > flowers and other weird, kitschy items. They also sell beeswax and
> > >paraffin
> > > > at prices far less than other stores.
> > >
> > >Keith, I realize this may be just superstition -- but doesn't the very
> > >thick glass have some kind of distorting effect?
> > >
> > >Judy
> >
> >
> >
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