[alt-photo] Re: NuArc UV units question

[Jeremy Moore]

Paul, you're asking for anecdotal evidence--but a multitude of anecdotes
never equals facts. You can develop a correlation bell-curve, but what use
is that in actually printing photographs?

I don't know that my NuArc is "working correctly", but it is consistent.
Since it is consistent I can rely on it to output the same amount of light
with each exposure. If everyone else prints using 500 units and I use 45
units do I or should I even care that I'm not using the same exposure as
long as my prints meet my expectations? I think the big thing in alt is
making the process work for you and not fitting your process to match that
of others--this is an art, not a science. If it was a science we wouldn't
ever need to print anything but step-wedges. It is science-mediated, but
that's not our end goal.

I've seen your work online and it looks good. So with the NuArc are you
making good prints? Is the light output consistent? This is easy to tell,
you print the same image on different days and does it look similar? You
know what you're doing and you understand that there are many variables and
you know what they are so you can take those into account. Yes, you switched
from printing with the sun to printing with a NuArc, but did you expect the
times to be the same?

Additionally, you just popped in with another point that makes me think you
didn't understand what I was trying to say--which is MY fault, I wasn't
doing a good enough job making myself understood:

"The fact that my negs for sun exposures for gum are 2 minutes or
(seemingly) 120-150 units on my NuArc, and that my sun exposures for pd are
7 minutes, make it seem strange that any pd exposure would be 45 units. This
is precisely the type of difference I'm trying to nail down in
troubleshooting my unit."

Since I didn't make myself clear on what a "unit" is with the NuArc and I
think you don't understand how the "units" on a NuArc work you're going to
have fundamental problems with troubleshooting because you won't know how to
construct an experimental model with any scientific rigor.

Everyone can go to the store and buy a yardstick. This yardstick is supposed
to be 36" long, but due to the manufacturing realities they are close enough
to 36" for common use. You can compare your yardstick to my yardstick and
you can compare it to Mark's yardstick and see how close we all are to get a
great idea of what 36" should be.

Now imagine when you go to the store you can buy wood in any length (your
piece of wood is 1 foot long or 25 feet long, it doesn't matter) and they
tell you this length is a yard and it is 36". This number of 36" is
meaningless because it's just whatever anyone chooses it to be--there's no
standard against which we can measure. If you got together 100 people to see
what their yard was you might come to a common consensus, but that consensus
still doesn't mean anything if people can still go to the store and buy wood
in any length and have it be 1 yard/36". We have a standard as to what an
inch is, we have no standard for the NuArc unit. There may be some general
consensus at NuArc as to what a unit is, but did ANY of us here buy our
NuArcs brand new and from NuArc? I bought mine from some guy who had it in
his garage in Oklahoma City and I have no idea what it was used for before
or what may have been done with it--this doesn't matter to me, what matters
to me is it outputs a consistent unit of light--whatever this unit may be.

This unit of light is also adjustable as I said in my previous email to the
list. I can tune the unit on my NuArc so that the amount of light I need to
make my pt/pd prints is 15 units, 45 units, 125 units, 250 units, 500
units--it's entirely fungible. If I can tune the unit on my machine to be 15
units or 500 units and output the same amount of light what use is it to
compare these units to the ones someone else is using. It would be just like
comparing our "yardsticks" where each of us can choose the length. In this
metaphor what is this length to us? The quantity of light to get the print
we want. There is a unit of measurement for this, it is called lumens, but
the NuArc "unit" has absolutely nothing to do with the standard of
measurement for light quantity that is lumens. Without recourse to a
standard of measurement getting into the nitty gritty of who uses what
number of units takes us back to comparing yardsticks that we each chose on
our own. I gave the standard I tune my unit to: with a new bulb 0.1 units at
full blast = 1 sec. How long is 0.1 units at full blast with your machine?
If you have this number we have a standard we can test against: at max power
what is the length of time it takes for your NuArc to click down 0.1 units?
If yours is 20 seconds then my 2 units is roughly equal to your 0.1 unit,
but if we don't know this then the comparison will never be fruitful. This
is why I said your question is pedantic, as it is overly concerned with
minute details to the detriment of getting you to where you want (making
prints)--that's my definition of pedantic. Many people think of pedantic in
a negative connotation, I don't and if you do then I apologize as there was
never any disrespect meant, it was how I was trying to explain my point.

-Jeremy-

On Mon, Apr 12, 2010 at 2:41 PM, Paul Viapiano <viapiano at pacbell.net> wrote:

> Jeremy, with all due respect, I don't believe that the question is pedantic
> at all.
>
> While there isn't a quantification/definition of a NuArc unit, there is an
> equivalency that can be expected in a particular model with a new bulb.
> That's the reason I asked the question. There is no one in my area that uses
> a NuArc for alt exposure and I was trying to compare against others to see
> if my unit was faulty.
>
> The fact that my negs for sun exposures for gum are 2 minutes or
> (seemingly) 120-150 units on my NuArc, and that my sun exposures for pd are
> 7 minutes, make it seem strange that any pd exposure would be 45 units. This
> is precisely the type of difference I'm trying to nail down in
> troubleshooting my unit.
>
> Until I replace the bulb and do all my testing, I was just trying to get a
> compendium of experiences...
>
> Paul
>
>
> ----- Original Message -----
> From: "Jeremy Moore" <jeremydmoore at gmail.com>
> To: "The alternative photographic processes mailing list" <
> alt-photo-process-list at lists.altphotolist.org>
> Sent: Monday, April 12, 2010 12:22 PM
> Subject: [alt-photo] Re: NuArc UV units question
>
>
> > Would it make a difference if I said 15 units, 45 units, 125 units, 250
> > units? Without a quantification of the amount of light against a known
> > standard--which there isn't with the NuArc "unit"--your question strikes
> me
> > as pedantic.
> >
> > I use 45 units.
> >
> > -Jeremy-
> >
> > On Sat, Apr 10, 2010 at 10:48 AM, Paul Viapiano <viapiano at pacbell.net
> >wrote:
> >
> >> OK, Jeremy...just curious here. How many units do you use to expose
> >> palladium with a new-ish bulb?
> >>
> >> p
> >>
> >>
> >>
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