----- Original Message -----
From: <eroustom@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Saturday, July 05, 2008 8:42 AM
Subject: [pure-silver] Re: Same Exposure Different Prints?
That's an interesting theory. They're all interesting,
thank you for the input all.
I forgot to mention that I use a Durst 606 condenser
enlarger with an incandescent 150 watt bulb.
Do these bulbs vary light strength based on heat?
The first print usually comes after much on-off for
focusing and light reading and composing. The second print
comes after about 10-15 minutes.
E.
Indescant lamps do not vary in output with temperature
as do gasseous discharge lamps. However, they _are_
sensitive to voltage. I suggest getting a cheap voltmeter
and monitoring the line. Voltage variations vary all over
the place depending on your electricity supplier and the
wiring in your house. If this turns out the be the problem
there are a couple of ways around it. I think Nicholas
Lindan's timer compensates for varying brightness, he can
confirm this, another is a Sola constant voltage
transformer. I also agree that checking out the lamp wiring
and socket is worth doing. Also check the voltage coming out
of the timer as well as the line voltage.
Since B&W prints are developed to "completion", meaning
until the contrast is maximum, there is likely to be little
variation from small changes in developing time provided you
develop long enough to reach this point. RC papers with
incorporated developer (those intended to be usable in rapid
access processing machines) will develop fully in one minute
in a strong developer like Dektol. Papers without developer
need at least 90 seconds and two minutes is a better routine
time. Exposure should be based on these times. Temperature
makes some difference but is not very critical provided its
not unusually high or low and assuming that it does not vary
a lot or very quickly, either of which would be very
unusual.
More information on your developing routine would be
useful.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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