Re: Question about NuArc 26-1K

Hi Sandy,

I have a NUARC, but I don't remember the model number—I do know it has a
metal hallide bulb.

I haven't noticed the problem you are talking about but then I don't expose
prints that close in time to eachother. The printing seems to be pretty
consistent.

My first guess is that it has to do with the successively longer drying times
affecting the moisture in the prints, assuming you are coating all 4 sheets
at once and then exposing them later,however, I would expect the opposite—less
density in each successive exposure.

I think Standford University had data on their site that PT/PD begins to lose
speed after about 1 hour after coating, but again...that's in the wrong
direction.

The prints getting successively darker does seem like an exposure issue.

You might try running the unit for a bit before exposing the first print, but
I don't know that it would solve the problem of seemingly successively
increased exposure.

Could there be a problem with your integrator?

I'm only guessing at these issues.

Have you talked to Sam? I know he felt that he needed to "warm up" his unit
so to speak before printing.

Mark Nelson
Precision Digital Negatives

In a message dated 8/17/05 2:27:32 PM, sanking@clemson.edu writes:

> 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
>
Received on Wed Aug 17 21:10:17 2005