Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Sun, 01 Aug 1999 07:29:45 -0400
Gary Miller wrote:
> ... Paper was
> humidified in a cool mist humidifier for 5 seconds on the front, 5 seconds
> on the back, and then 5 seconds on the front in the cases where noted.
This seems rather quick to humidify a paper with the thickness of
Platine, but could be appropriate at the 65% RH. Do you judge it's
readiness (humidification) by feeling and listening for amount of
crispness or lack thereof???
> ...
> Test 2:
> ...
> Result: Showed less solarization than Test #1
> Exposure range : Step 4/5-17
This seems to indicate some dependence of the solarization on the metal
concentration, but did not show up in the conclusions. I would suggest
to not dismiss the relationship between metal concentration and
solarization just yet.
> ...
> CONCLUSIONS;
> ...
> 3. Use of Tween 20 (10%) seems to be the cause of the solarization/bronzing
> effect in my system when used in the sensitizer coating on Platine. Tween
> 20 had no adverse effects when used in the solution coated onto Cranes
> Platinotype
Even after reading the past posts on Tween 20, I have never understood
its purpose nor have I ever required what it is claimed to be able to
do.
>
> 4. Pre-humidifying the paper prior to coating produced worse results for me
> than not humidifying with increased contrast and graining seen.
I have used Arches Platine and have not noticed any "graining" due to
pre-humidification. Also I am assuming the by "results" you're
referring to solarization. There are several benefits to
pre-humidification (unrelated to solarization) which could be somewhat
hidden or reduced by the 65% RH.
> ...
> 5. Average exposure time with the Platine was about 6 mins. In the same
> formulation on Cranes Platinotype exposure time was 16 mins on average.
> ...
This is unusual. As I have never found this much difference in exposure
time for these two papers (same negative, same chem. same processing), I
would suspect that some other aspect is at work here.
Also we should keep in mind that these solarization effects may be due
to interrelated factors. Such as if less contrast agent is use or metal
concentrations optimized or different ambient conditions, a similar run
of tests may produce some different outcomes. We already know that
different papers can have different outcomes from the same series of
tests.
Thanks for your contribution of information.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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