Re: cyanotype question

From: Sam Wang ^lt;[email protected]>
Date: 09/03/04-08:34:29 AM Z
Message-id: <>


Delayed development does indeed alter the tonal relationship, sometimes quite a bit. I have used this
method to help tame papers that were too contrasty otherwise - by delaying as long as 24 hours. Judy
mentioned that delaying just 15 minutes (or was it 30?) would make a difference.

On the integrator question, I have experienced strange irregularity with the one on my NUARC. Even
though Sandy questioned my sanity when I told him that, my experience shows that the exposures are
not always exactly the same - it seems to need to warm up before being more consistent.

> From: Joe Smigiel <>
> Date: 2004/09/02 Thu PM 11:13:08 EDT

If this is actually happening due to some temporal effect between exposure and processing then simply
processing two similarly exposed strips (say 250 units each) with some delay between them (e.g., 30
minutes), should produce different tonal scales. That would be easy enough to check by identically
exposing one strip and then the other sequentially rather than giving an identical simultaneous
exposure to both.
> Maybe what is happening is that the UV exposure produced by the NuArc is decreasing as the bulb
heats up and stays on for an extended time after the brief restarts when I pulled one strip from the
unit. I had assumed the integrator controlled the output though so that sort of variation wouldn't
> Has anyone else found the UV output to decrease from one of these units with an integrator as
exposures are lengthened? Maybe I've just got a bad integrator. Does anyone know if the integrators
need to be periodically calibrated/adjusted in some way?
> Joe
Received on Fri Sep 3 09:01:13 2004

This archive was generated by hypermail 2.1.8 : 10/01/04-09:17:54 AM Z CST