Re: Question about NuArc 26-1K

       Hi Sandy,
       All I can offer is what little I know and for the most part is
speculation .....
       I have a 26-1K as well as a few other different brand units..... I
do not use the Nuarc but had some plans to build a UV enlarger with it
using the head as the enlargers light source.............. So to me this
news is very disappointing........
       The only thing it could be is that the bulb when heated over a
specified time period gives off more UV output at a greater intensity as
more mercury vaporizes......... The NuArc units do not have a shutter
mechanism plus the integrators may not be that sensitive to measure the UV
intensity.... I have noticed that NuArc cuts corners on all their
equipment where ever possible from everything from their lenses to their
cabinetry... I would not be surprise if their integrator circuitry as well
as their transformers follow suite, ................
         I think comparatively speaking , NuArc is second rate to a Olec ,
Ascore, or DooLith ...............If you compare a NuArc to a lets say a
Olec unit you will find the there is quite a difference..... A Olec or
Ascore unit have shutters in them that will not open till the bulb has
reached a certain temperature or UV output.......... I do not think any
serious established print shop would have been using NuArc equipment
...........
         The units are designed for plate making which is a little different
than making multiple prints......You will probably have to adjust your
program timing to compensate for what you have discovered..........
My 2 bits......
John Cremati.
----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Wednesday, August 17, 2005 3:24 PM
Subject: Question about NuArc 26-1K

> This week I have been printing some multiples of a negative in
> palladium, exposing with a NuArc 26-1K. I have experienced a lot of
> difficulty in printing exact duplicates, even though the integrator
> appears to be working as it should. The situation is that I am
> printing one after the other, with just enough time between each
> printing to change the negative from one piece of sensitized paper to
> the next. What I am finding is that each printing results in slightly
> greater density on the print than the last, with the last of four
> about 1/4 stop more dense than the first of four. I develop all four
> prints at the same time so processing is not an issue.
>
> I thought for a while that the problem was a coating one, but nothing
> I did to get greater consistency in coating helped. Then I decided to
> try to print the negatives with my BLB exposure unit, which is also
> controlled by a light integrator. Result. Four prints of identical
> density. And just to be sure I did it again with the BLB unit with
> the same result.
>
> So I appear to have a problem with the NuArc, but why? If I only
> print once and then not again for 15-20 minutes I get perfectly
> consistent exposures with the NuArc. What appears to be the case is
> that as the bulb heats up the response of the integrator is changed.
> But why?
>
> Would like to hear from other NuArc 26-1k users to know if you have
> been able to make exact duplicates printing the way I described above.
>
> Sandy
>
>
>
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Received on Wed Aug 17 17:27:56 2005