rurmonas@senet.com.au
Date: 11/07/02-03:14:55 AM Z
Wow, a lot of replies to my query, thank you all.
Let me answer various questions.
I started this whole clearing investigation after noticing a yellowish
stain in the highlights and around the edges of the print, where it
had been masked from exposure. I worked my way down to finding that
simply coating and drying was enough check for clearing.
Eric reminded me that I had intended to try washing in distilled water.
So last night I tried one batch in filtered water (filtered through a
mechanical + carbon filter) and also a batch in distilled water.
This test used 5 different papers. The result was very little difference
from the tap water. One of the marginal papers seemed a bit clearer.
During this test I checked the clearing as it was being washed. The
thing I noted was that the papers which clear, do so very quickly.
Within 30 seconds there is little trace of the coating. The marginal
papers were a bit slower.
I think Kees may have the found the cause. I had trouble getting
"good" green citrate, but found some local industry is using large amounts
of the brown citrate. As a result I can get high grade brown cheaply
and know it is "fresh". So if the brown citrate does cause staining, this
would explain my problem.
So does anyone have a suggestion for a bath which could remove the brown
citrate stain, without damaging the blue image? I guess otherwise
I will need to stick to the papers which do not stain.
As an aside, while I have no experience with the green citrate, I have
not noticed any speed issues with using the brown. Using a good
negative (i.e. not over or under exposed) it takes 12 minutes exposure
to full sun for my preffered paper / processing sequence. I can get
a properly exposed print in just 2min 30 seconds of full sun with
a different paper / processing sequence, but the blue tends to
"spread" on that paper.
Richard
--- Richard Urmonas rurmonas@senet.com.au ------------------------------------------------- This mail sent through SE Net Webmail http://webmail.senet.com.au
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